Issue trace events to gather repaint information.

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
diff --git a/Source/core/frame/FrameView.cpp b/Source/core/frame/FrameView.cpp
index 8ec58d08914a74881c9cdea69332274fb6a15fda..59ad514deea1eca0ea508c6c18df028f30359785 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -1040,6 +1040,8 @@ void FrameView::repaintTree(RenderObject* root)
     // we continue to track repaint rects until this function is called.
     ASSERT(!m_nestedLayoutCount);
 
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "FrameView::repaintTree");
+
     // FIXME: really, we're in the repaint phase here, and the compositing queries are legal.
     // Until those states are fully fledged, I'll just disable the ASSERTS.
     DisableCompositingQueryAsserts disabler;