Bug 1290823 - Send Gesture:SingleTap even if we're in a chrome document. r=rbarker

MozReview-Commit-ID: 8fRAVdUpM9j

--HG--
extra : rebase_source : 1e29b96467390b2d11b4b1f8976eda1e4fe9aca0

widget/android/AndroidContentController.cpp

@@ -48,21 +48,22 @@ AndroidContentController::DispatchSingleTapToObservers(const LayoutDevicePoint&
                                                        const ScrollableLayerGuid& aGuid) const
 {
     nsIContent* content = nsLayoutUtils::FindContentFor(aGuid.mScrollId);
-    nsIPresShell* shell = content
-        ? mozilla::layers::APZCCallbackHelper::GetRootContentDocumentPresShellForContent(content)
+    nsPresContext* context = content
+        ? mozilla::layers::APZCCallbackHelper::GetPresContextForContent(content)
         : nullptr;
 
-    if (!shell || !shell->GetPresContext()) {
-        return;
+    if (!context) {
+      return;
     }
 
     CSSPoint point = mozilla::layers::APZCCallbackHelper::ApplyCallbackTransform(
-        aPoint / shell->GetPresContext()->CSSToDevPixelScale(), aGuid);
+        aPoint / context->CSSToDevPixelScale(), aGuid);
 
-    if (shell->ScaleToResolution()) {
+    nsPresContext* rcdContext = context->GetToplevelContentDocumentPresContext();
+    if (rcdContext && rcdContext->PresShell()->ScaleToResolution()) {
         // We need to convert from the root document to the root content document,
         // by unapplying the resolution that's on the content document.
-        const float resolution = shell->GetResolution();
+        const float resolution = rcdContext->PresShell()->GetResolution();
         point.x /= resolution;
         point.y /= resolution;
     }