[Invalidation Tracking] Add trace events for compositor based invalidations

Source/core/rendering/compositing/GraphicsLayerUpdater.h

Index: Source/core/rendering/compositing/GraphicsLayerUpdater.h
diff --git a/Source/core/rendering/compositing/GraphicsLayerUpdater.h b/Source/core/rendering/compositing/GraphicsLayerUpdater.h
index e3c8a6bc967ac9a4483f544a4e480e6c1bce8e1d..8d414f9686d1eb7d8b5e40f286cfd79b6e2a09fd 100644
--- a/Source/core/rendering/compositing/GraphicsLayerUpdater.h
+++ b/Source/core/rendering/compositing/GraphicsLayerUpdater.h
@@ -33,6 +33,8 @@ namespace blink {
 
 class RenderLayer;
 
+typedef Vector<std::pair<RenderLayer*, const char*> > LayersNeedingPaintInvalidation;
+
 class GraphicsLayerUpdater {
 
 public:
@@ -44,7 +46,7 @@ public:
         ForceUpdate,
     };
 
-    void update(RenderLayer&, Vector<RenderLayer*>& layersNeedingPaintInvalidation);
+    void update(RenderLayer&, LayersNeedingPaintInvalidation&);
 
     bool needsRebuildTree() const { return m_needsRebuildTree; }
 
@@ -55,7 +57,7 @@ public:
 private:
     class UpdateContext;
 
-    void updateRecursive(RenderLayer&, UpdateType, const UpdateContext&, Vector<RenderLayer*>& layersNeedingPaintInvalidation);
+    void updateRecursive(RenderLayer&, UpdateType, const UpdateContext&, LayersNeedingPaintInvalidation&);
 
     bool m_needsRebuildTree;
 };