Implement incremental paint property tree rebuilding

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
index 88b7f0127e81e629468b821ec2e872c4b6e3d1bf..c05ed444ea282084bcfcc1c71712107085d113ed 100644
--- a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
@@ -83,11 +83,18 @@ struct PaintPropertyTreeBuilderContext {
 class PaintPropertyTreeBuilder {
  public:
   PaintPropertyTreeBuilderContext setupInitialContext();
-  void buildTreeNodes(FrameView&, PaintPropertyTreeBuilderContext&);
-  void buildTreeNodesForSelf(const LayoutObject&,
-                             PaintPropertyTreeBuilderContext&);
-  void buildTreeNodesForChildren(const LayoutObject&,
-                                 PaintPropertyTreeBuilderContext&);
+  // Update the paint properties for |FrameView| if needed, and always update
+  // the context.
+  void updateProperties(FrameView&, PaintPropertyTreeBuilderContext&);
+
+  // Update the paint properties that affect this |LayoutObject| (e.g.,
+  // properties like paint offset) if needed, and always update the context.
+  void updatePropertiesForSelf(const LayoutObject&,
+                               PaintPropertyTreeBuilderContext&);
+  // Update the paint properties that affect children of this |LayoutObject|
+  // (e.g., scroll offset transform) if needed, and always update the context.
+  void updatePropertiesForChildren(const LayoutObject&,
+                                   PaintPropertyTreeBuilderContext&);
 
  private:
   static void updatePaintOffsetTranslation(const LayoutObject&,