Auto merge of #26793 - paulrouget:prefAPI, r=Manishearth

Pref api

Needs a bit more tweaking, but this should be ready soon.

Fix #26445

<img width="991" alt="Screen Shot 2020-06-03 at 14 59 57" src="https://user-images.githubusercontent.com/373579/83848819-b538ca00-a70e-11ea-9da8-67c9c2fe60d8.png">

15 files changed, 545 insertions, 118 deletions

diff --git a/support/hololens/ServoApp/App.h b/support/hololens/ServoApp/App.h
index 4772306e91f..3820da8b952 100644
--- a/support/hololens/ServoApp/App.h
+++ b/support/hololens/ServoApp/App.h
@@ -6,19 +6,19 @@
 #include "App.xaml.g.h"
 
 namespace winrt::ServoApp::implementation {
+using namespace winrt::Windows::Foundation;
+using namespace winrt::Windows::UI::Xaml;
+using namespace winrt::Windows::ApplicationModel;
+using namespace winrt::Windows::ApplicationModel::Activation;
+
 struct App : AppT<App> {
   App();
 
-  void createRootFrame(winrt::Windows::UI::Xaml::Controls::Frame &, bool,
-                       winrt::Windows::Foundation::IInspectable const &);
-  void OnLaunched(
-      Windows::ApplicationModel::Activation::LaunchActivatedEventArgs const &);
-  void App::OnActivated(
-      Windows::ApplicationModel::Activation::IActivatedEventArgs const &);
-  void OnSuspending(IInspectable const &,
-                    Windows::ApplicationModel::SuspendingEventArgs const &);
-  void OnNavigationFailed(
-      IInspectable const &,
-      Windows::UI::Xaml::Navigation::NavigationFailedEventArgs const &);
+  void createRootFrame(Controls::Frame &, bool, IInspectable const &);
+  void OnLaunched(LaunchActivatedEventArgs const &);
+  void App::OnActivated(IActivatedEventArgs const &);
+  void OnSuspending(IInspectable const &, SuspendingEventArgs const &);
+  void OnNavigationFailed(IInspectable const &,
+                          Navigation::NavigationFailedEventArgs const &);
 };
 } // namespace winrt::ServoApp::implementation
diff --git a/support/hololens/ServoApp/App.xaml b/support/hololens/ServoApp/App.xaml
index 015f637b3df..333b37f88b7 100644
--- a/support/hololens/ServoApp/App.xaml
+++ b/support/hololens/ServoApp/App.xaml
@@ -4,4 +4,8 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:local="using:ServoApp">
 
+    <Application.Resources>
+        <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
+    </Application.Resources>
+
 </Application>
diff --git a/support/hololens/ServoApp/Assets/UI/stop.png b/support/hololens/ServoApp/Assets/UI/cross.png
index 181ede7b298..181ede7b298 100644
--- a/support/hololens/ServoApp/Assets/UI/stop.png
+++ b/support/hololens/ServoApp/Assets/UI/cross.png
diff --git a/support/hololens/ServoApp/BrowserPage.cpp b/support/hololens/ServoApp/BrowserPage.cpp
index e8ba12ba2b3..a2b13bf60b9 100644
--- a/support/hololens/ServoApp/BrowserPage.cpp
+++ b/support/hololens/ServoApp/BrowserPage.cpp
@@ -8,6 +8,11 @@
 #include "BrowserPage.g.cpp"
 #include "DefaultUrl.h"
 
+#include "winrt/Microsoft.UI.Xaml.Controls.h"
+#include "winrt/Microsoft.UI.Xaml.XamlTypeInfo.h"
+#include "winrt/Windows.UI.Text.h"
+#include "winrt/Windows.UI.Xaml.Documents.h" // For Run.Text()
+
 using namespace std::placeholders;
 using namespace winrt::Windows::Foundation;
 using namespace winrt::Windows::UI::Xaml;
@@ -18,6 +23,7 @@ using namespace winrt::Windows::UI::Notifications;
 using namespace winrt::Windows::Data::Xml::Dom;
 
 namespace winrt::ServoApp::implementation {
+
 BrowserPage::BrowserPage() {
   InitializeComponent();
   BindServoEvents();
@@ -84,13 +90,12 @@ void BrowserPage::BindServoEvents() {
       });
 }
 
-void BrowserPage::OnURLFocused(Windows::Foundation::IInspectable const &) {
+void BrowserPage::OnURLFocused(IInspectable const &) {
   urlTextbox().SelectAll();
 }
 
 void BrowserPage::OnURLKeyboardAccelerator(
-    Windows::Foundation::IInspectable const &,
-    Windows::UI::Xaml::Input::KeyboardAcceleratorInvokedEventArgs const &) {
+    IInspectable const &, Input::KeyboardAcceleratorInvokedEventArgs const &) {
   urlTextbox().Focus(FocusState::Programmatic);
 }
 
@@ -116,10 +121,7 @@ void BrowserPage::SetTransientMode(bool transient) {
 
 void BrowserPage::SetArgs(hstring args) { servoControl().SetArgs(args); }
 
-void BrowserPage::Shutdown() {
-  ToastNotificationManager::History().Clear();
-  servoControl().Shutdown();
-}
+void BrowserPage::Shutdown() { servoControl().Shutdown(); }
 
 /**** USER INTERACTIONS WITH UI ****/
 
@@ -148,23 +150,153 @@ void BrowserPage::OnHomeButtonClicked(IInspectable const &,
   servoControl().LoadURIOrSearch(DEFAULT_URL);
 }
 
+// Given a pref, update its associated UI control.
+void BrowserPage::UpdatePref(ServoApp::Pref pref, Controls::Control ctrl) {
+  auto value = pref.Value();
+  auto type = value.as<IPropertyValue>().Type();
+  if (type == PropertyType::Boolean) {
+    ctrl.as<Controls::CheckBox>().IsChecked(unbox_value<bool>(value));
+  } else if (type == PropertyType::Double) {
+    ctrl.as<Microsoft::UI::Xaml::Controls::NumberBox>().Value(
+        unbox_value<double>(value));
+  } else if (type == PropertyType::Int64) {
+    ctrl.as<Microsoft::UI::Xaml::Controls::NumberBox>().Value(
+        (double)unbox_value<int64_t>(value));
+  } else if (type == PropertyType::String) {
+    ctrl.as<Controls::TextBox>().Text(unbox_value<hstring>(value));
+  }
+  auto stack = ctrl.Parent().as<Controls::StackPanel>();
+  auto font = winrt::Windows::UI::Text::FontWeights::Normal();
+  if (!pref.IsDefault()) {
+    font = winrt::Windows::UI::Text::FontWeights::Bold();
+  }
+  stack.Children().GetAt(0).as<Controls::TextBlock>().FontWeight(font);
+  stack.Children().GetAt(2).as<Controls::Button>().IsEnabled(!pref.IsDefault());
+}
+
+// Retrieve the preference list from Servo and build the preference table.
+void BrowserPage::BuildPrefList() {
+  // It would be better to use a template and bindings, but the
+  // <ListView> takes too long to generate all the items, and
+  // it's pretty difficiult to have different controls depending
+  // on the pref type.
+  prefList().Children().Clear();
+  for (auto pref : ServoControl().Preferences()) {
+    auto value = pref.Value();
+    auto type = value.as<IPropertyValue>().Type();
+    std::optional<Controls::Control> ctrl;
+    if (type == PropertyType::Boolean) {
+      auto checkbox = Controls::CheckBox();
+      checkbox.IsChecked(unbox_value<bool>(value));
+      checkbox.Click([=](const auto &, auto const &) {
+        auto upref = ServoControl().SetBoolPref(
+            pref.Key(), checkbox.IsChecked().GetBoolean());
+        UpdatePref(upref, checkbox);
+      });
+      ctrl = checkbox;
+    } else if (type == PropertyType::String) {
+      auto textbox = Controls::TextBox();
+      textbox.Text(unbox_value<hstring>(value));
+      textbox.KeyUp([=](const auto &, Input::KeyRoutedEventArgs const &e) {
+        if (e.Key() == Windows::System::VirtualKey::Enter) {
+          auto upref = ServoControl().SetStringPref(pref.Key(), textbox.Text());
+          UpdatePref(upref, textbox);
+        }
+      });
+      ctrl = textbox;
+    } else if (type == PropertyType::Int64) {
+      // Note: These are *not* under Windows::UI:Xaml namespace.
+      auto nbox = Microsoft::UI::Xaml::Controls::NumberBox();
+      nbox.Value((double)unbox_value<int64_t>(value));
+      nbox.SpinButtonPlacementMode(
+          Microsoft::UI::Xaml::Controls::NumberBoxSpinButtonPlacementMode::
+              Inline);
+      nbox.ValueChanged([=](const auto &, const auto &) {
+        int val = (int)nbox.Value();
+        auto upref = ServoControl().SetIntPref(pref.Key(), val);
+        UpdatePref(upref, nbox);
+      });
+      ctrl = nbox;
+    } else if (type == PropertyType::Double) {
+      auto nbox = Microsoft::UI::Xaml::Controls::NumberBox();
+      nbox.Value(unbox_value<double>(value));
+      nbox.ValueChanged([=](const auto &, const auto &) {
+        auto upref =
+            ServoControl().SetIntPref(pref.Key(), (int64_t)nbox.Value());
+        UpdatePref(upref, (Controls::Control &)nbox);
+      });
+      ctrl = nbox;
+    }
+    if (ctrl.has_value()) {
+      auto stack = Controls::StackPanel();
+      stack.Tag(winrt::box_value(pref.Key()));
+      stack.Padding({4, 4, 4, 4});
+      stack.Orientation(Controls::Orientation::Horizontal);
+      auto key = Controls::TextBlock();
+      key.Text(pref.Key());
+      key.Width(350);
+      if (!pref.IsDefault()) {
+        auto font = winrt::Windows::UI::Text::FontWeights::Bold();
+        key.FontWeight(font);
+      }
+      stack.Children().Append(key);
+      ctrl->Width(300);
+      ctrl->Margin({4, 0, 40, 0});
+      stack.Children().Append(*ctrl);
+      auto reset = Controls::Button();
+      reset.Content(winrt::box_value(L"reset"));
+      reset.IsEnabled(!pref.IsDefault());
+      reset.Click([=](const auto &, auto const &) {
+        auto upref = ServoControl().ResetPref(pref.Key());
+        UpdatePref(upref, *ctrl);
+      });
+      stack.Children().Append(reset);
+      prefList().Children().Append(stack);
+    }
+  }
+}
+
+void BrowserPage::OnPrefererenceSearchboxEdited(
+    IInspectable const &, Input::KeyRoutedEventArgs const &) {
+  auto input = preferenceSearchbox().Text();
+  for (auto element : prefList().Children()) {
+    auto ctrl = (Controls::Control &)element;
+    if (input.size() == 0) {
+      ctrl.Visibility(Visibility::Visible);
+    } else {
+      auto tag = ctrl.Tag();
+      std::wstring key = static_cast<std::wstring>(unbox_value<hstring>(tag));
+      bool not_found = key.find(input) == std::wstring::npos;
+      ctrl.Visibility(not_found ? Visibility::Collapsed : Visibility::Visible);
+    }
+  }
+}
+
 void BrowserPage::OnDevtoolsButtonClicked(IInspectable const &,
                                           RoutedEventArgs const &) {
-  auto toastTemplate = ToastTemplateType::ToastText01;
-  auto toastXml = ToastNotificationManager::GetTemplateContent(toastTemplate);
-  auto toastTextElements = toastXml.GetElementsByTagName(L"text");
-  std::wstring message;
-  if (mDevtoolsStatus == DevtoolsStatus::Stopped) {
-    message = L"Devtools server hasn't started";
-  } else if (mDevtoolsStatus == DevtoolsStatus::Running) {
-    message = L"DevTools server has started on port " +
-              std::to_wstring(mDevtoolsPort);
-  } else if (mDevtoolsStatus == DevtoolsStatus::Failed) {
-    message = L"Error: could not start DevTools";
+  if (toolbox().Visibility() == Visibility::Visible) {
+    prefList().Children().Clear();
+    toolbox().Visibility(Visibility::Collapsed);
+    return;
+  }
+
+  toolbox().Visibility(Visibility::Visible);
+
+  BuildPrefList();
+
+  // FIXME: we could use template + binding for this.
+  auto ok = mDevtoolsStatus == DevtoolsStatus::Running ? Visibility::Visible
+                                                       : Visibility::Collapsed;
+  auto ko = mDevtoolsStatus == DevtoolsStatus::Failed ? Visibility::Visible
+                                                      : Visibility::Collapsed;
+  auto wip = mDevtoolsStatus == DevtoolsStatus::Stopped ? Visibility::Visible
+                                                        : Visibility::Collapsed;
+  DevtoolsStatusOK().Visibility(ok);
+  DevtoolsStatusKO().Visibility(ko);
+  DevtoolsStatusWIP().Visibility(wip);
+  if (mDevtoolsStatus == DevtoolsStatus::Running) {
+    DevtoolsPort().Text(std::to_wstring(mDevtoolsPort));
   }
-  toastTextElements.Item(0).InnerText(message);
-  auto toast = ToastNotification(toastXml);
-  ToastNotificationManager::CreateToastNotifier().Show(toast);
 }
 
 void BrowserPage::OnURLEdited(IInspectable const &,
@@ -177,15 +309,13 @@ void BrowserPage::OnURLEdited(IInspectable const &,
   }
 }
 
-void BrowserPage::OnMediaControlsPlayClicked(
-    Windows::Foundation::IInspectable const &,
-    Windows::UI::Xaml::RoutedEventArgs const &) {
+void BrowserPage::OnMediaControlsPlayClicked(IInspectable const &,
+                                             RoutedEventArgs const &) {
   servoControl().SendMediaSessionAction(
       static_cast<int32_t>(servo::Servo::MediaSessionActionType::Play));
 }
-void BrowserPage::OnMediaControlsPauseClicked(
-    Windows::Foundation::IInspectable const &,
-    Windows::UI::Xaml::RoutedEventArgs const &) {
+void BrowserPage::OnMediaControlsPauseClicked(IInspectable const &,
+                                              RoutedEventArgs const &) {
   servoControl().SendMediaSessionAction(
       static_cast<int32_t>(servo::Servo::MediaSessionActionType::Pause));
 }
diff --git a/support/hololens/ServoApp/BrowserPage.h b/support/hololens/ServoApp/BrowserPage.h
index bb57afad68a..bae31d22ff3 100644
--- a/support/hololens/ServoApp/BrowserPage.h
+++ b/support/hololens/ServoApp/BrowserPage.h
@@ -9,6 +9,10 @@
 
 namespace winrt::ServoApp::implementation {
 
+using namespace winrt::Windows;
+using namespace winrt::Windows::Foundation;
+using namespace winrt::Windows::UI::Xaml;
+
 static const hstring SERVO_SCHEME = L"fxr";
 static const hstring SERVO_SCHEME_SLASH_SLASH = L"fxr://";
 
@@ -16,35 +20,32 @@ struct BrowserPage : BrowserPageT<BrowserPage> {
 public:
   BrowserPage();
 
-  void OnForwardButtonClicked(Windows::Foundation::IInspectable const &,
-                              Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnBackButtonClicked(Windows::Foundation::IInspectable const &,
-                           Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnReloadButtonClicked(Windows::Foundation::IInspectable const &,
-                             Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnStopButtonClicked(Windows::Foundation::IInspectable const &,
-                           Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnHomeButtonClicked(Windows::Foundation::IInspectable const &,
-                           Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnDevtoolsButtonClicked(Windows::Foundation::IInspectable const &,
-                               Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnURLEdited(Windows::Foundation::IInspectable const &,
-                   Windows::UI::Xaml::Input::KeyRoutedEventArgs const &);
-  void OnURLFocused(Windows::Foundation::IInspectable const &);
-  void OnURLKeyboardAccelerator(
-      Windows::Foundation::IInspectable const &,
-      Windows::UI::Xaml::Input::KeyboardAcceleratorInvokedEventArgs const &);
+  void OnForwardButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnBackButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnReloadButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnStopButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnHomeButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnDevtoolsButtonClicked(IInspectable const &, RoutedEventArgs const &);
+  void OnURLEdited(IInspectable const &, Input::KeyRoutedEventArgs const &);
+  void OnURLFocused(IInspectable const &);
+  void
+  OnURLKeyboardAccelerator(IInspectable const &,
+                           Input::KeyboardAcceleratorInvokedEventArgs const &);
   void Shutdown();
-  void LoadServoURI(Windows::Foundation::Uri uri);
+  void LoadServoURI(Uri uri);
   void SetTransientMode(bool);
   void SetArgs(hstring);
-  void OnMediaControlsPlayClicked(Windows::Foundation::IInspectable const &,
-                                  Windows::UI::Xaml::RoutedEventArgs const &);
-  void OnMediaControlsPauseClicked(Windows::Foundation::IInspectable const &,
-                                   Windows::UI::Xaml::RoutedEventArgs const &);
+  void OnMediaControlsPlayClicked(IInspectable const &,
+                                  RoutedEventArgs const &);
+  void OnMediaControlsPauseClicked(IInspectable const &,
+                                   RoutedEventArgs const &);
+  void OnPrefererenceSearchboxEdited(IInspectable const &,
+                                     Input::KeyRoutedEventArgs const &);
 
 private:
+  void UpdatePref(ServoApp::Pref, Controls::Control);
   void BindServoEvents();
+  void BuildPrefList();
   DevtoolsStatus mDevtoolsStatus = DevtoolsStatus::Stopped;
   unsigned int mDevtoolsPort = 0;
 };
diff --git a/support/hololens/ServoApp/BrowserPage.xaml b/support/hololens/ServoApp/BrowserPage.xaml
index 3fa6cf84982..da4ea5c9792 100644
--- a/support/hololens/ServoApp/BrowserPage.xaml
+++ b/support/hololens/ServoApp/BrowserPage.xaml
@@ -6,7 +6,11 @@
     xmlns:local="using:ServoApp"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:muxc="using:Microsoft.UI.Xaml.Controls"
     mc:Ignorable="d">
+
+
+
     <Page.Resources>
         <Style x:Key="NavigationBarButton" TargetType="Button">
             <Setter Property="Background" Value="Transparent"/>
@@ -82,7 +86,9 @@
     <Grid VerticalAlignment="Stretch">
         <Grid.RowDefinitions>
             <RowDefinition Height="auto"/>
-            <RowDefinition Height="*"/>
+            <RowDefinition Height="*" MinHeight="200"/>
+            <RowDefinition Height="auto"/>
+            <RowDefinition Height="auto"/>
             <RowDefinition Height="auto"/>
         </Grid.RowDefinitions>
         <Grid Grid.Row="0" x:Name="navigationBar" Background="{ThemeResource InkToolbarButtonBackgroundThemeBrush}">
@@ -111,7 +117,7 @@
                     </Button.KeyboardAccelerators>
                 </Button>
                 <Button Style="{StaticResource NavigationBarButton}" x:Name="stopButton" IsTabStop="true" IsEnabled="false" Visibility="Collapsed" Click="OnStopButtonClicked" AutomationProperties.Name="Stop" ToolTipService.ToolTip="Stop">
-                    <Image Source="Assets/UI/stop.png" Height="18"></Image>
+                    <Image Source="Assets/UI/cross.png" Height="18"></Image>
                     <Button.KeyboardAccelerators>
                         <KeyboardAccelerator Key="Escape" Modifiers="None" />
                     </Button.KeyboardAccelerators>
@@ -132,9 +138,49 @@
                 <ProgressRing x:Name="urlbarLoadingIndicator" Margin="10,0"/>
             </StackPanel>
         </Grid>
-        <local:ServoControl TabIndex="0" x:Name="servoControl" Grid.Row="1"/>
-        <ProgressBar x:Name="transientLoadingIndicator" Visibility="Collapsed" Grid.Row="2"/>
-        <CommandBar Grid.Row="2" x:Name="mediaControls" Visibility="Collapsed">
+        <local:ServoControl Grid.Row="1" TabIndex="0" x:Name="servoControl"/>
+        <muxc:TabView x:Name="toolbox" IsAddTabButtonVisible="False" Grid.Row="2" Visibility="Collapsed" Height="300">
+            <muxc:TabView.TabStripFooter>
+                <Grid>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="*"/>
+                        <ColumnDefinition Width="Auto"/>
+                    </Grid.ColumnDefinitions>
+                    <Button Grid.Column="1" Style="{StaticResource NavigationBarButton}" x:Name="toolboxCloseButton" IsTabStop="true" Click="OnDevtoolsButtonClicked">
+                        <Image Source="Assets/UI/cross.png" Height="18"></Image>
+                    </Button>
+                </Grid>
+            </muxc:TabView.TabStripFooter>
+            <muxc:TabViewItem Header="Devtools Server" IsClosable="False">
+                <StackPanel>
+                    <TextBlock x:Name="DevtoolsStatusOK" Visibility="Collapsed" Margin="10">
+                        <Run>Devtools server is listening on port </Run>
+                        <Run FontWeight="Bold" x:Name="DevtoolsPort"></Run>
+                        <Run>.</Run>
+                    </TextBlock>
+                    <TextBlock x:Name="DevtoolsStatusKO" Visibility="Collapsed">
+                        <Run>Devtools server failed to start.</Run>
+                    </TextBlock>
+                    <TextBlock x:Name="DevtoolsStatusWIP" Visibility="Collapsed">
+                        <Run>Devtools server is starting..</Run>
+                    </TextBlock>
+                </StackPanel>
+            </muxc:TabViewItem>
+            <muxc:TabViewItem Header="Preferences" IsClosable="False">
+                <Grid VerticalAlignment="Stretch">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="auto"/>
+                        <RowDefinition Height="*"/>
+                    </Grid.RowDefinitions>
+                    <TextBox Grid.Row="0" Text="" IsTabStop="true" PlaceholderText="Search preferences" x:Name="preferenceSearchbox" VerticalAlignment="Center" KeyUp="OnPrefererenceSearchboxEdited" IsSpellCheckEnabled="False" Margin="3"/>
+                    <ScrollViewer Grid.Row="1" VerticalScrollBarVisibility="Auto">
+                        <StackPanel x:Name="prefList"/>
+                    </ScrollViewer>
+                </Grid>
+            </muxc:TabViewItem>
+        </muxc:TabView>
+        <ProgressBar x:Name="transientLoadingIndicator" Visibility="Collapsed" Grid.Row="3"/>
+        <CommandBar Grid.Row="4" x:Name="mediaControls" Visibility="Collapsed">
             <AppBarButton Icon="Play" Label="Play" x:Name="playButton" Visibility="Collapsed" Click="OnMediaControlsPlayClicked"/>
             <AppBarButton Icon="Pause" Label="Pause" x:Name="pauseButton" Click="OnMediaControlsPauseClicked"/>
         </CommandBar>
diff --git a/support/hololens/ServoApp/ServoApp.vcxproj b/support/hololens/ServoApp/ServoApp.vcxproj
index b005f746086..9d0c1c7716b 100644
--- a/support/hololens/ServoApp/ServoApp.vcxproj
+++ b/support/hololens/ServoApp/ServoApp.vcxproj
@@ -907,7 +907,7 @@
     <Image Include="Assets\UI\forward.png" />
     <Image Include="Assets\UI\home.png" />
     <Image Include="Assets\UI\reload.png" />
-    <Image Include="Assets\UI\stop.png" />
+    <Image Include="Assets\UI\cross.png" />
     <Image Include="Assets\Wide310x150Logo.scale-100.png" />
     <Image Include="Assets\Wide310x150Logo.scale-200.png" />
     <Image Include="Assets\Wide310x150Logo.scale-400.png" />
@@ -948,6 +948,7 @@
     <Import Project="..\packages\Microsoft.Windows.CppWinRT.2.0.200316.3\build\native\Microsoft.Windows.CppWinRT.targets" Condition="Exists('..\packages\Microsoft.Windows.CppWinRT.2.0.200316.3\build\native\Microsoft.Windows.CppWinRT.targets')" />
     <Import Project="..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.targets" Condition="Exists('..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.targets')" />
     <Import Project="..\packages\ANGLE.WindowsStore.Servo.2.1.19\build\native\ANGLE.WindowsStore.Servo.targets" Condition="Exists('..\packages\ANGLE.WindowsStore.Servo.2.1.19\build\native\ANGLE.WindowsStore.Servo.targets')" />
+    <Import Project="..\packages\Microsoft.UI.Xaml.2.4.2\build\native\Microsoft.UI.Xaml.targets" Condition="Exists('..\packages\Microsoft.UI.Xaml.2.4.2\build\native\Microsoft.UI.Xaml.targets')" />
   </ImportGroup>
   <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
@@ -958,5 +959,6 @@
     <Error Condition="!Exists('..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.props'))" />
     <Error Condition="!Exists('..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\OpenXR.Loader.1.0.6.2\build\native\OpenXR.Loader.targets'))" />
     <Error Condition="!Exists('..\packages\ANGLE.WindowsStore.Servo.2.1.19\build\native\ANGLE.WindowsStore.Servo.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\ANGLE.WindowsStore.Servo.2.1.19\build\native\ANGLE.WindowsStore.Servo.targets'))" />
+    <Error Condition="!Exists('..\packages\Microsoft.UI.Xaml.2.4.2\build\native\Microsoft.UI.Xaml.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Microsoft.UI.Xaml.2.4.2\build\native\Microsoft.UI.Xaml.targets'))" />
   </Target>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/support/hololens/ServoApp/ServoApp.vcxproj.filters b/support/hololens/ServoApp/ServoApp.vcxproj.filters
index aa50cafbcd4..39acc9fc3c3 100644
--- a/support/hololens/ServoApp/ServoApp.vcxproj.filters
+++ b/support/hololens/ServoApp/ServoApp.vcxproj.filters
@@ -148,7 +148,7 @@
     <Image Include="Assets\UI\reload.png">
       <Filter>Assets\UI</Filter>
     </Image>
-    <Image Include="Assets\UI\stop.png">
+    <Image Include="Assets\UI\cross.png">
       <Filter>Assets\UI</Filter>
     </Image>
     <Image Include="Assets\UI\home.png">
@@ -901,4 +901,4 @@
   <ItemGroup>
     <ApplicationDefinition Include="App.xaml" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/support/hololens/ServoApp/ServoControl/Servo.cpp b/support/hololens/ServoApp/ServoControl/Servo.cpp
index 83d926087fb..a53ea2489f1 100644
--- a/support/hololens/ServoApp/ServoControl/Servo.cpp
+++ b/support/hololens/ServoApp/ServoControl/Servo.cpp
@@ -1,6 +1,7 @@
 #include "pch.h"
 #include "Servo.h"
 #include <EGL/egl.h>
+#include "../DefaultUrl.h"
 
 namespace winrt::servo {
 
@@ -130,10 +131,64 @@ Servo::Servo(hstring url, hstring args, GLsizei width, GLsizei height,
     : mWindowHeight(height), mWindowWidth(width), mDelegate(aDelegate) {
   SetEnvironmentVariableA("PreviewRuntimeEnabled", "1");
 
+  Windows::Storage::ApplicationDataContainer localSettings =
+      Windows::Storage::ApplicationData::Current().LocalSettings();
+  if (!localSettings.Containers().HasKey(L"servoUserPrefs")) {
+    Windows::Storage::ApplicationDataContainer container =
+        localSettings.CreateContainer(
+            L"servoUserPrefs",
+            Windows::Storage::ApplicationDataCreateDisposition::Always);
+  }
+
+  auto prefs = localSettings.Containers().Lookup(L"servoUserPrefs");
+
+  if (!prefs.Values().HasKey(L"shell.homepage")) {
+    prefs.Values().Insert(L"shell.homepage", box_value(DEFAULT_URL));
+  }
+
+  if (!prefs.Values().HasKey(L"dom.webxr.enabled")) {
+    prefs.Values().Insert(L"dom.webxr.enabled", box_value(true));
+  }
+
+  std::vector<capi::CPref> cprefs;
+
+  for (auto pref : prefs.Values()) {
+    auto key = *hstring2char(pref.Key());
+    auto value = pref.Value();
+    auto type = value.as<Windows::Foundation::IPropertyValue>().Type();
+    capi::CPref pref;
+    pref.key = key;
+    pref.pref_type = capi::CPrefType::Missing;
+    pref.value = NULL;
+    if (type == Windows::Foundation::PropertyType::Boolean) {
+      pref.pref_type = capi::CPrefType::Bool;
+      auto val = unbox_value<bool>(value);
+      pref.value = &val;
+    } else if (type == Windows::Foundation::PropertyType::String) {
+      pref.pref_type = capi::CPrefType::Str;
+      pref.value = *hstring2char(unbox_value<hstring>(value));
+    } else if (type == Windows::Foundation::PropertyType::Int64) {
+      pref.pref_type = capi::CPrefType::Int;
+      auto val = unbox_value<int64_t>(value);
+      pref.value = &val;
+    } else if (type == Windows::Foundation::PropertyType::Double) {
+      pref.pref_type = capi::CPrefType::Float;
+      auto val = unbox_value<double>(value);
+      pref.value = &val;
+    } else if (type == Windows::Foundation::PropertyType::Empty) {
+      pref.pref_type = capi::CPrefType::Missing;
+    } else {
+      log("skipping pref %s. Unknown type", key);
+      continue;
+    }
+    cprefs.push_back(pref);
+  }
+
+  capi::CPrefList prefsList = {cprefs.size(), cprefs.data()};
+
   capi::CInitOptions o;
-  hstring defaultPrefs = L" --pref dom.webxr.enabled --devtools";
-  o.args = *hstring2char(args + defaultPrefs);
-  o.url = *hstring2char(url);
+  o.prefs = &prefsList;
+  o.args = *hstring2char(args + L"--devtools");
   o.width = mWindowWidth;
   o.height = mWindowHeight;
   o.density = dpi;
@@ -221,6 +276,96 @@ Servo::~Servo() {
     CloseHandle(sLogHandle);
 }
 
+Servo::PrefTuple Servo::SetFloatPref(hstring key, double val) {
+  auto ckey = *hstring2char(key);
+  capi::set_float_pref(ckey, val);
+  auto updatedPref = WrapPref(capi::get_pref(ckey));
+  SaveUserPref(updatedPref);
+  return updatedPref;
+}
+
+Servo::PrefTuple Servo::SetIntPref(hstring key, int64_t val) {
+  auto ckey = *hstring2char(key);
+  capi::set_int_pref(ckey, val);
+  auto updatedPref = WrapPref(capi::get_pref(ckey));
+  SaveUserPref(updatedPref);
+  return updatedPref;
+}
+
+Servo::PrefTuple Servo::SetBoolPref(hstring key, bool val) {
+  auto ckey = *hstring2char(key);
+  capi::set_bool_pref(ckey, val);
+  auto updatedPref = WrapPref(capi::get_pref(ckey));
+  SaveUserPref(updatedPref);
+  return updatedPref;
+}
+
+Servo::PrefTuple Servo::SetStringPref(hstring key, hstring val) {
+  auto ckey = *hstring2char(key);
+  auto cval = *hstring2char(val);
+  capi::set_str_pref(ckey, cval);
+  auto updatedPref = WrapPref(capi::get_pref(ckey));
+  SaveUserPref(updatedPref);
+  return updatedPref;
+}
+
+Servo::PrefTuple Servo::ResetPref(hstring key) {
+  auto ckey = *hstring2char(key);
+  capi::reset_pref(ckey);
+  auto updatedPref = WrapPref(capi::get_pref(ckey));
+  SaveUserPref(updatedPref);
+  return updatedPref;
+}
+
+void Servo::SaveUserPref(PrefTuple pref) {
+  auto localSettings =
+      Windows::Storage::ApplicationData::Current().LocalSettings();
+  auto values = localSettings.Containers().Lookup(L"servoUserPrefs").Values();
+  auto [key, val, isDefault] = pref;
+  if (isDefault) {
+    values.Remove(key);
+  } else {
+    values.Insert(key, val);
+  }
+}
+
+Servo::PrefTuple Servo::WrapPref(capi::CPref pref) {
+  winrt::Windows::Foundation::IInspectable val;
+  if (pref.pref_type == capi::CPrefType::Bool) {
+    val = box_value(*(capi::get_pref_as_bool(pref.value)));
+  } else if (pref.pref_type == capi::CPrefType::Int) {
+    val = box_value(*(capi::get_pref_as_int(pref.value)));
+  } else if (pref.pref_type == capi::CPrefType::Float) {
+    val = box_value(*(capi::get_pref_as_float(pref.value)));
+  } else if (pref.pref_type == capi::CPrefType::Str) {
+    val = box_value(char2hstring(capi::get_pref_as_str(pref.value)));
+  }
+  auto key = char2hstring(pref.key);
+  auto isDefault = pref.is_default;
+  Servo::PrefTuple t{key, val, isDefault};
+  return t;
+}
+
+Servo::PrefTuple Servo::GetPref(hstring key) {
+  auto ckey = *hstring2char(key);
+  return WrapPref(capi::get_pref(ckey));
+}
+
+std::vector<Servo::PrefTuple> Servo::GetPrefs() {
+  if (sServo == nullptr) {
+    return {};
+  }
+  auto prefs = capi::get_prefs();
+  std::vector<
+      std::tuple<hstring, winrt::Windows::Foundation::IInspectable, bool>>
+      vec;
+  for (auto i = 0; i < prefs.len; i++) {
+    auto pref = WrapPref(prefs.list[i]);
+    vec.push_back(pref);
+  }
+  return vec;
+}
+
 winrt::hstring char2hstring(const char *c_str) {
   // FIXME: any better way of doing this?
   auto str = std::string(c_str);
diff --git a/support/hololens/ServoApp/ServoControl/Servo.h b/support/hololens/ServoApp/ServoControl/Servo.h
index a61adf81f49..025b0f30c3f 100644
--- a/support/hololens/ServoApp/ServoControl/Servo.h
+++ b/support/hololens/ServoApp/ServoControl/Servo.h
@@ -17,6 +17,8 @@ extern "C" {
 }
 } // namespace capi
 
+using namespace capi;
+
 hstring char2hstring(const char *);
 std::unique_ptr<char *> hstring2char(hstring);
 
@@ -29,62 +31,67 @@ public:
   ~Servo();
   ServoDelegate &Delegate() { return mDelegate; }
 
-  typedef capi::CMouseButton MouseButton;
-  typedef capi::CPromptResult PromptResult;
-  typedef capi::CContextMenuResult ContextMenuResult;
-  typedef capi::CMediaSessionActionType MediaSessionActionType;
-  typedef capi::CMediaSessionPlaybackState MediaSessionPlaybackState;
-  typedef capi::CDevtoolsServerState DevtoolsServerState;
-
-  void PerformUpdates() { capi::perform_updates(); }
-  void DeInit() { capi::deinit(); }
-  void RequestShutdown() { capi::request_shutdown(); }
-  void SetBatchMode(bool mode) { capi::set_batch_mode(mode); }
-  void GoForward() { capi::go_forward(); }
-  void GoBack() { capi::go_back(); }
-  void Click(float x, float y) { capi::click(x, y); }
-  void MouseDown(float x, float y, capi::CMouseButton b) {
-    capi::mouse_down(x, y, b);
-  }
-  void MouseUp(float x, float y, capi::CMouseButton b) {
-    capi::mouse_up(x, y, b);
-  }
-  void TouchDown(float x, float y, int32_t id) { capi::touch_down(x, y, id); }
-  void TouchUp(float x, float y, int32_t id) { capi::touch_up(x, y, id); }
-  void TouchMove(float x, float y, int32_t id) { capi::touch_move(x, y, id); }
-  void TouchCancel(float x, float y, int32_t id) {
-    capi::touch_cancel(x, y, id);
-  }
-  void MouseMove(float x, float y) { capi::mouse_move(x, y); }
-
-  void Reload() { capi::reload(); }
-  void Stop() { capi::stop(); }
-  bool LoadUri(hstring uri) { return capi::load_uri(*hstring2char(uri)); }
-  void ChangeVisibility(bool visible) { capi::change_visibility(visible); }
-  bool IsUriValid(hstring uri) {
-    return capi::is_uri_valid(*hstring2char(uri));
-  }
+  typedef std::tuple<hstring, winrt::Windows::Foundation::IInspectable, bool>
+      PrefTuple;
+  static std::vector<PrefTuple> GetPrefs();
+  static PrefTuple GetPref(hstring key);
+  static PrefTuple SetBoolPref(hstring key, bool val);
+  static PrefTuple SetStringPref(hstring key, hstring val);
+  static PrefTuple SetIntPref(hstring key, int64_t val);
+  static PrefTuple SetFloatPref(hstring key, double val);
+  static PrefTuple ResetPref(hstring key);
+
+  typedef CMouseButton MouseButton;
+  typedef CPromptResult PromptResult;
+  typedef CContextMenuResult ContextMenuResult;
+  typedef CMediaSessionActionType MediaSessionActionType;
+  typedef CMediaSessionPlaybackState MediaSessionPlaybackState;
+  typedef CDevtoolsServerState DevtoolsServerState;
+  typedef CPrefType CPrefType;
+
+  void PerformUpdates() { perform_updates(); }
+  void DeInit() { deinit(); }
+  void RequestShutdown() { request_shutdown(); }
+  void SetBatchMode(bool mode) { set_batch_mode(mode); }
+  void GoForward() { go_forward(); }
+  void GoBack() { go_back(); }
+  void Click(float x, float y) { click(x, y); }
+  void MouseDown(float x, float y, CMouseButton b) { mouse_down(x, y, b); }
+  void MouseUp(float x, float y, CMouseButton b) { mouse_up(x, y, b); }
+  void TouchDown(float x, float y, int32_t id) { touch_down(x, y, id); }
+  void TouchUp(float x, float y, int32_t id) { touch_up(x, y, id); }
+  void TouchMove(float x, float y, int32_t id) { touch_move(x, y, id); }
+  void TouchCancel(float x, float y, int32_t id) { touch_cancel(x, y, id); }
+  void MouseMove(float x, float y) { mouse_move(x, y); }
+
+  void Reload() { reload(); }
+  void Stop() { stop(); }
+  bool LoadUri(hstring uri) { return load_uri(*hstring2char(uri)); }
+  void ChangeVisibility(bool visible) { change_visibility(visible); }
+  bool IsUriValid(hstring uri) { return is_uri_valid(*hstring2char(uri)); }
   void Scroll(float dx, float dy, float x, float y) {
-    capi::scroll((int32_t)dx, (int32_t)dy, (int32_t)x, (int32_t)y);
+    scroll((int32_t)dx, (int32_t)dy, (int32_t)x, (int32_t)y);
   }
   void SetSize(GLsizei width, GLsizei height) {
     if (width != mWindowWidth || height != mWindowHeight) {
       mWindowWidth = width;
       mWindowHeight = height;
-      capi::resize(mWindowWidth, mWindowHeight);
+      resize(mWindowWidth, mWindowHeight);
     }
   }
-  void SendMediaSessionAction(capi::CMediaSessionActionType action) {
-    capi::media_session_action(action);
+  void SendMediaSessionAction(CMediaSessionActionType action) {
+    media_session_action(action);
   }
-  void ContextMenuClosed(capi::CContextMenuResult res, unsigned int idx) {
-    capi::on_context_menu_closed(res, idx);
+  void ContextMenuClosed(CContextMenuResult res, unsigned int idx) {
+    on_context_menu_closed(res, idx);
   }
 
 private:
   ServoDelegate &mDelegate;
   GLsizei mWindowWidth;
   GLsizei mWindowHeight;
+  static void SaveUserPref(PrefTuple);
+  static PrefTuple WrapPref(CPref cpref);
 };
 
 class ServoDelegate {
diff --git a/support/hololens/ServoApp/ServoControl/ServoControl.cpp b/support/hololens/ServoApp/ServoControl/ServoControl.cpp
index eae5016181c..cca58cce0ac 100644
--- a/support/hololens/ServoApp/ServoControl/ServoControl.cpp
+++ b/support/hololens/ServoApp/ServoControl/ServoControl.cpp
@@ -1,6 +1,7 @@
 #include "pch.h"
 #include "ServoControl.h"
 #include "ServoControl.g.cpp"
+#include "Pref.g.cpp"
 #include <stdlib.h>
 
 using namespace std::placeholders;
@@ -275,10 +276,19 @@ hstring ServoControl::LoadURIOrSearch(hstring input) {
   }
 
   // Doesn't look like a URI. Let's search for the string.
-  hstring searchUri =
-      L"https://duckduckgo.com/html/?q=" + Uri::EscapeComponent(input);
-  TryLoadUri(searchUri);
-  return searchUri;
+  auto escapedInput = Uri::EscapeComponent(input);
+  std::wstring searchUri =
+      unbox_value<hstring>(std::get<1>(Servo::GetPref(L"shell.searchpage")))
+          .c_str();
+  std::wstring keyword = L"%s";
+  size_t start_pos = searchUri.find(keyword);
+  if (start_pos == std::string::npos)
+    searchUri = searchUri + escapedInput;
+  else
+    searchUri.replace(start_pos, keyword.length(), escapedInput);
+  hstring finalUri{searchUri};
+  TryLoadUri(finalUri);
+  return finalUri;
 }
 
 void ServoControl::SendMediaSessionAction(int32_t action) {
@@ -580,4 +590,13 @@ template <typename Callable> void ServoControl::RunOnUIThread(Callable cb) {
   Dispatcher().RunAsync(CoreDispatcherPriority::High, cb);
 }
 
+Collections::IVector<ServoApp::Pref> ServoControl::Preferences() {
+  std::vector<ServoApp::Pref> prefs;
+  for (auto [key, val, isDefault] : Servo::GetPrefs()) {
+    prefs.push_back(ServoApp::Pref(key, val, isDefault));
+  }
+  return winrt::single_threaded_observable_vector<ServoApp::Pref>(
+      std::move(prefs));
+}
+
 } // namespace winrt::ServoApp::implementation
diff --git a/support/hololens/ServoApp/ServoControl/ServoControl.h b/support/hololens/ServoApp/ServoControl/ServoControl.h
index dbc9e91ca92..6b0d09bafc5 100644
--- a/support/hololens/ServoApp/ServoControl/ServoControl.h
+++ b/support/hololens/ServoApp/ServoControl/ServoControl.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "ServoControl.g.h"
+#include "Pref.g.h"
 #include "OpenGLES.h"
 #include "Servo.h"
 #include "DefaultUrl.h"
@@ -7,10 +8,30 @@
 using namespace winrt::Windows::Foundation::Collections;
 
 namespace winrt::ServoApp::implementation {
+
+struct Pref : PrefT<Pref> {
+public:
+  Pref(hstring key, IInspectable value, bool isDefault) {
+    mKey = key;
+    mValue = value;
+    mIsDefault = isDefault;
+  };
+  IInspectable Value() { return mValue; }
+  hstring Key() { return mKey; }
+  bool IsDefault() { return mIsDefault; }
+
+private:
+  hstring mKey;
+  IInspectable mValue;
+  bool mIsDefault;
+};
+
 struct ServoControl : ServoControlT<ServoControl>, public servo::ServoDelegate {
 
   ServoControl();
 
+  Windows::Foundation::Collections::IVector<ServoApp::Pref> Preferences();
+
   void GoBack();
   void GoForward();
   void Reload();
@@ -20,6 +41,36 @@ struct ServoControl : ServoControlT<ServoControl>, public servo::ServoDelegate {
   hstring LoadURIOrSearch(hstring);
   void SendMediaSessionAction(int32_t);
 
+  ServoApp::Pref SetBoolPref(hstring aKey, bool aVal) {
+    auto [key, val, isDefault] = servo::Servo::SetBoolPref(aKey, aVal);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
+  ServoApp::Pref SetStringPref(hstring aKey, hstring aVal) {
+    auto [key, val, isDefault] = servo::Servo::SetStringPref(aKey, aVal);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
+  ServoApp::Pref SetIntPref(hstring aKey, int64_t aVal) {
+    auto [key, val, isDefault] = servo::Servo::SetIntPref(aKey, aVal);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
+  ServoApp::Pref SetFloatPref(hstring aKey, double aVal) {
+    auto [key, val, isDefault] = servo::Servo::SetFloatPref(aKey, aVal);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
+  ServoApp::Pref ResetPref(hstring aKey) {
+    auto [key, val, isDefault] = servo::Servo::ResetPref(aKey);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
+  ServoApp::Pref GetPref(hstring aKey) {
+    auto [key, val, isDefault] = servo::Servo::GetPref(aKey);
+    return ServoApp::Pref(key, val, isDefault);
+  }
+
   void OnLoaded(IInspectable const &,
                 Windows::UI::Xaml::RoutedEventArgs const &);
 
@@ -223,4 +274,5 @@ private:
 namespace winrt::ServoApp::factory_implementation {
 struct ServoControl
     : ServoControlT<ServoControl, implementation::ServoControl> {};
+struct Pref : PrefT<Pref, implementation::Pref> {};
 } // namespace winrt::ServoApp::factory_implementation
diff --git a/support/hololens/ServoApp/ServoControl/ServoControl.idl b/support/hololens/ServoApp/ServoControl/ServoControl.idl
index 5e5da81bc29..99f411a9be4 100644
--- a/support/hololens/ServoApp/ServoControl/ServoControl.idl
+++ b/support/hololens/ServoApp/ServoControl/ServoControl.idl
@@ -11,6 +11,14 @@ namespace ServoApp {
     Failed,
   };
 
+  runtimeclass Pref
+  {
+    Pref(String key, IInspectable val, Boolean isDefault);
+    IInspectable Value { get; };
+    String Key { get; };
+    Boolean IsDefault { get; };
+  }
+
   runtimeclass ServoControl : Windows.UI.Xaml.Controls.Control {
       ServoControl();
       void GoBack();
@@ -33,5 +41,12 @@ namespace ServoApp {
       event Windows.Foundation.EventHandler<String> OnURLChanged;
       event MediaSessionMetadataDelegate OnMediaSessionMetadata;
       event Windows.Foundation.EventHandler<int> OnMediaSessionPlaybackStateChange;
+      Windows.Foundation.Collections.IVector<Pref> Preferences { get; };
+      Pref GetPref(String key);
+      Pref SetBoolPref(String key, Boolean val);
+      Pref SetIntPref(String key, Int64 val);
+      Pref SetFloatPref(String key, Double val);
+      Pref SetStringPref(String key, String val);
+      Pref ResetPref(String key);
 }
 } // namespace ServoApp
diff --git a/support/hololens/ServoApp/packages.config b/support/hololens/ServoApp/packages.config
index 2a6918a8e78..c6bb3977b3c 100644
--- a/support/hololens/ServoApp/packages.config
+++ b/support/hololens/ServoApp/packages.config
@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="ANGLE.WindowsStore.Servo" version="2.1.19" targetFramework="native" />
+  <package id="Microsoft.UI.Xaml" version="2.4.2" targetFramework="native" />
   <package id="Microsoft.Windows.CppWinRT" version="2.0.200316.3" targetFramework="native" />
   <package id="OpenXR.Loader" version="1.0.6.2" targetFramework="native" />
 </packages>
\ No newline at end of file
diff --git a/support/hololens/ServoApp/pch.h b/support/hololens/ServoApp/pch.h
index 59a4cd3ca8a..04ea55755e9 100644
--- a/support/hololens/ServoApp/pch.h
+++ b/support/hololens/ServoApp/pch.h
@@ -54,3 +54,8 @@
 #include <winrt/Windows.UI.Xaml.Navigation.h>
 #include <winrt/Windows.UI.Notifications.h>
 #include <winrt/Windows.Data.Xml.Dom.h>
+
+#include "winrt/Microsoft.UI.Xaml.Automation.Peers.h"
+#include "winrt/Microsoft.UI.Xaml.Controls.Primitives.h"
+#include "winrt/Microsoft.UI.Xaml.Media.h"
+#include "winrt/Microsoft.UI.Xaml.XamlTypeInfo.h"
\ No newline at end of file