Fix hit testing inside layers.

* Prevent asking for a sync in GraphicsLayerAndroid if some property has not
  changed.
* Remove scrolling logic from LayerAndroid and create a subclass for scrollable
  layers.
* Report the scrolling limits to the layer in order to scroll iframes (not
  turned on) and to avoid computing them each time the layer is scrolled.
* Change the foreground rect calculations to better match the non-overflow case.
* During hit testing, intersect the hitTestClip with the foreground and
  background to prevent false positives in the layer.
* Prepare for iframe scrolling by adding code to trigger compositing for
  iframes.  This currently works great except for navigation so it disabled for
  now.

Bug: 3258631
Change-Id: I0da2d8dbe25376c6aa4f485c9350048c82c6f563

1 files changed, 3 insertions, 1 deletions

diff --git a/WebCore/platform/graphics/android/GraphicsLayerAndroid.h b/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
index 098ad37..ea8c5c9 100644
--- a/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
+++ b/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
@@ -32,6 +32,8 @@ class Image;
 
 namespace WebCore {
 
+class ScrollableLayerAndroid;
+
 class GraphicsLayerAndroid : public GraphicsLayer {
 public:
 
@@ -149,7 +151,7 @@ private:
     Vector<FloatRect> m_invalidatedRects;
 
     LayerAndroid* m_contentLayer;
-    LayerAndroid* m_foregroundLayer;
+    ScrollableLayerAndroid* m_foregroundLayer;
     LayerAndroid* m_foregroundClipLayer;
 };