UI-side layer merging

Merge multiple painted layers into a LayerGroup to share a dualTiledTexture

see LayerAndroid::canJoinGroup() for merging rules

Change-Id: I5f5b156894c3743825f570b47d34e905d74de10a

2 files changed, 15 insertions, 1 deletions

diff --git a/Source/WebCore/rendering/RenderLayer.h b/Source/WebCore/rendering/RenderLayer.h
index 02ab8e9..5e421f0 100644
--- a/Source/WebCore/rendering/RenderLayer.h
+++ b/Source/WebCore/rendering/RenderLayer.h
@@ -498,6 +498,12 @@ public:
     bool hasOverflowScroll() const { return m_hasOverflowScroll; }
     bool hasOverflowParent() const;
 #endif
+#if PLATFORM(ANDROID)
+    bool intrinsicallyComposited() const { return m_intrinsicallyComposited; }
+    void setIntrinsicallyComposited(bool intrinsicallyComposited) {
+        m_intrinsicallyComposited = intrinsicallyComposited;
+    }
+#endif
 
 private:
     // The normal operator new is disallowed on all render objects.
@@ -751,6 +757,9 @@ protected:
     bool m_shouldComposite : 1;
 #endif
 #endif
+#if PLATFORM(ANDROID)
+    bool m_intrinsicallyComposited : 1;
+#endif
 
     bool m_containsDirtyOverlayScrollbars : 1;
 #if ENABLE(ANDROID_OVERFLOW_SCROLL)
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
index 25a08e7..d7f5c6b 100644
--- a/Source/WebCore/rendering/RenderLayerCompositor.cpp
+++ b/Source/WebCore/rendering/RenderLayerCompositor.cpp
@@ -682,7 +682,12 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* layer, O
     layer->updateLayerPosition();
     layer->updateZOrderLists();
     layer->updateNormalFlowList();
-    
+#if PLATFORM(ANDROID)
+    RenderObject* renderer = layer->renderer();
+    bool intCom = requiresCompositingLayer(layer);
+    layer->setIntrinsicallyComposited(intCom);
+#endif
+
     // Clear the flag
     layer->setHasCompositingDescendant(false);