Issue trace events to gather repaint information.

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 1022 matching lines @@
 // let the compositor pick which to actually draw.
 // See http://crbug.com/306706
 void FrameView::repaintTree(RenderObject* root)
 {
     ASSERT(RuntimeEnabledFeatures::repaintAfterLayoutEnabled());
     ASSERT(!root->needsLayout());
     // We should only repaint for the outer most layout. This works as
     // 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;
 
     for (RenderObject* renderer = root; renderer; renderer = renderer->nextInPreOrder()) {
         const LayoutRect& oldRepaintRect = renderer->oldRepaintRect();
         const LayoutRect& newRepaintRect = renderer->newRepaintRect();
 
         if ((renderer->onlyNeededPositionedMovementLayout() && renderer->compositingState() != PaintsIntoOwnBacking)
             || (renderer->shouldDoFullRepaintIfSelfPaintingLayer()
@@ skipping 2200 matching lines @@
 void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
     ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
     if (AXObjectCache* cache = axObjectCache()) {
         cache->remove(scrollbar);
         cache->handleScrollbarUpdate(this);
     }
 }
 
 } // namespace WebCore