3 files changed, 24 insertions, 24 deletions
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index a2d6d4bac5a..d9d6f624f16 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -433,29 +433,16 @@ impl HTMLIFrameElementMethods for HTMLIFrameElement {
     // Experimental mozbrowser implementation is based on the webidl
     // present in the gecko source tree, and the documentation here:
     // https://developer.mozilla.org/en-US/docs/Web/API/Using_the_Browser_API
-
-    // TODO(gw): Use experimental codegen when it is available to avoid
-    // exposing these APIs. See https://github.com/servo/servo/issues/5264.
-
     // https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attr-mozbrowser
     fn Mozbrowser(&self) -> bool {
-        // We don't want to allow mozbrowser iframes within iframes
-        let is_root_pipeline = window_from_node(self).parent_info().is_none();
-        if mozbrowser_enabled() && is_root_pipeline {
-            let element = self.upcast::<Element>();
-            element.has_attribute(&atom!("mozbrowser"))
-        } else {
-            false
-        }
+        let element = self.upcast::<Element>();
+        element.has_attribute(&atom!("mozbrowser"))
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attr-mozbrowser
-    fn SetMozbrowser(&self, value: bool) -> ErrorResult {
-        if mozbrowser_enabled() {
-            let element = self.upcast::<Element>();
-            element.set_bool_attribute(&atom!("mozbrowser"), value);
-        }
-        Ok(())
+    fn SetMozbrowser(&self, value: bool) {
+        let element = self.upcast::<Element>();
+        element.set_bool_attribute(&atom!("mozbrowser"), value);
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/goBack
diff --git a/components/script/dom/webidls/HTMLIFrameElement.webidl b/components/script/dom/webidls/HTMLIFrameElement.webidl
index 20bb563e908..0d78b56fb98 100644
--- a/components/script/dom/webidls/HTMLIFrameElement.webidl
+++ b/components/script/dom/webidls/HTMLIFrameElement.webidl
@@ -32,8 +32,8 @@ partial interface HTMLIFrameElement {
 };
 
 partial interface HTMLIFrameElement {
-  [ChromeOnly,SetterThrows,Pref="dom.mozbrowser.enabled"]
-           attribute boolean mozbrowser;
+    [Func="Window::global_is_mozbrowser"]
+    attribute boolean mozbrowser;
 };
 
 HTMLIFrameElement implements BrowserElement;
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 63a0ca2a36e..a46cac12296 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -14,7 +14,7 @@ use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, ScrollToOptions};
 use dom::bindings::codegen::Bindings::WindowBinding::{self, FrameRequestCallback, WindowMethods};
 use dom::bindings::error::{Error, Fallible, report_pending_exception};
-use dom::bindings::global::GlobalRef;
+use dom::bindings::global::{GlobalRef, global_root_from_object};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::num::Finite;
@@ -37,9 +37,8 @@ use dom::storage::Storage;
 use euclid::{Point2D, Rect, Size2D};
 use gfx_traits::LayerId;
 use ipc_channel::ipc::{self, IpcSender};
-use js::jsapi::{Evaluate2, MutableHandleValue};
-use js::jsapi::{HandleValue, JSContext};
-use js::jsapi::{JSAutoCompartment, JS_GC, JS_GetRuntime, SetWindowProxy};
+use js::jsapi::{Evaluate2, HandleObject, HandleValue, JSAutoCompartment, JSContext};
+use js::jsapi::{JS_GetRuntime, JS_GC, MutableHandleValue, SetWindowProxy};
 use js::rust::CompileOptionsWrapper;
 use js::rust::Runtime;
 use layout_interface::{ContentBoxResponse, ContentBoxesResponse, ResolvedStyleResponse, ScriptReflow};
@@ -93,6 +92,7 @@ use timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle, OneshotTimers
 use tinyfiledialogs::{self, MessageBoxIcon};
 use url::Url;
 use util::geometry::{self, MAX_RECT};
+use util::prefs::mozbrowser_enabled;
 use util::str::HTML_SPACE_CHARACTERS;
 use util::{breakpoint, opts};
 use webdriver_handlers::jsval_to_webdriver;
@@ -1432,6 +1432,19 @@ impl Window {
             context.active_window()
         })
     }
+
+    /// Returns whether mozbrowser is enabled and `obj` has been created
+    /// in a top-level `Window` global.
+    #[allow(unsafe_code)]
+    pub unsafe fn global_is_mozbrowser(_: *mut JSContext, obj: HandleObject) -> bool {
+        if !mozbrowser_enabled() {
+            return false;
+        }
+        match global_root_from_object(obj.get()).r() {
+            GlobalRef::Window(window) => window.parent_info().is_none(),
+            _ => false,
+        }
+    }
 }
 
 impl Window {