Bug 1287576 - Extract a helper method to update a frame to the touch target document's root frame. No functional changes. r=botond

MozReview-Commit-ID: 3SRxAfTeMR

gfx/layers/apz/util/APZCCallbackHelper.cpp

@@ -554,6 +554,24 @@ GetRootDocumentElementFor(nsIWidget* aWidget)
   return nullptr;
 }
 
+static nsIFrame*
+UpdateRootFrameForTouchTargetDocument(nsIFrame* aRootFrame)
+{
+#if defined(MOZ_ANDROID_APZ)
+  // Re-target so that the hit test is performed relative to the frame for the
+  // Root Content Document instead of the Root Document which are different in
+  // Android. See bug 1229752 comment 16 for an explanation of why this is necessary.
+  if (nsIDocument* doc = aRootFrame->PresContext()->PresShell()->GetTouchEventTargetDocument()) {
+    if (nsIPresShell* shell = doc->GetShell()) {
+      if (nsIFrame* frame = shell->GetRootFrame()) {
+        return frame;
+      }
+    }
+  }
+#endif
+  return aRootFrame;
+}
+
 // Determine the scrollable target frame for the given point and add it to
 // the target list. If the frame doesn't have a displayport, set one.
 // Return whether or not a displayport was set.
@@ -564,19 +582,6 @@ PrepareForSetTargetAPZCNotification(nsIWidget* aWidget,
                                     const LayoutDeviceIntPoint& aRefPoint,
                                     nsTArray<ScrollableLayerGuid>* aTargets)
 {
-#if defined(MOZ_ANDROID_APZ)
-  // Re-target so that the hit test is performed relative to the frame for the
-  // Root Content Document instead of the Root Document which are different in
-  // Android. See bug 1229752 comment 16 for an explanation of why this is necessary.
-  if (nsIDocument* doc = aRootFrame->PresContext()->PresShell()->GetTouchEventTargetDocument()) {
-    if (nsIPresShell* shell = doc->GetShell()) {
-      if(nsIFrame* frame = shell->GetRootFrame()) {
-        aRootFrame = frame;
-      }
-    }
-  }
-#endif
-
   ScrollableLayerGuid guid(aGuid.mLayersId, 0, FrameMetrics::NULL_SCROLL_ID);
   nsPoint point =
     nsLayoutUtils::GetEventCoordinatesRelativeTo(aWidget, aRefPoint, aRootFrame);
@@ -739,6 +744,8 @@ APZCCallbackHelper::SendSetTargetAPZCNotification(nsIWidget* aWidget,
   sLastTargetAPZCNotificationInputBlock = aInputBlockId;
   if (nsIPresShell* shell = aDocument->GetShell()) {
     if (nsIFrame* rootFrame = shell->GetRootFrame()) {
+      rootFrame = UpdateRootFrameForTouchTargetDocument(rootFrame);
+
       bool waitForRefresh = false;
       nsTArray<ScrollableLayerGuid> targets;