Auto merge of #23696 - servo:hl, r=jdm

Add UWP port - bis

This is #23658 with some fixes:
- removed nspr from DLL dependencies (was breaking VS build)
- exclude symbols from header file (was breaking VS build)
- rebased

Before merging:
- please check the rebased commit that introduces the `--uwp` option (things moved around since https://github.com/servo/servo/commit/7c85dc09b59e653caf60cb18d3b3fdea2ba4d4ae)
- should we wait until the WR fix lands upstream?

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23696)
<!-- Reviewable:end -->

1 files changed, 29 insertions, 0 deletions

diff --git a/support/hololens/App.xaml.cpp b/support/hololens/App.xaml.cpp
new file mode 100644
index 00000000000..e084de34b43
--- /dev/null
+++ b/support/hololens/App.xaml.cpp
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "pch.h"
+#include "App.xaml.h"
+
+using namespace hlservo;
+
+App::App()
+{
+    InitializeComponent();
+}
+
+void App::OnLaunched(Windows::ApplicationModel::Activation::LaunchActivatedEventArgs ^ e)
+{
+#if _DEBUG
+    if (IsDebuggerPresent()) {
+        DebugSettings->EnableFrameRateCounter = true;
+    }
+#endif
+
+    if (mPage == nullptr) {
+        mPage = ref new OpenGLESPage(&mOpenGLES);
+    }
+
+    Windows::UI::Xaml::Window::Current->Content = mPage;
+    Windows::UI::Xaml::Window::Current->Activate();
+}