Add RAIL tracing category to Chrome tracing.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2416 matching lines @@
     DisableCompositingQueryAsserts disabler;
     // Allow throttling to make sure no painting paths (e.g.,
     // ContentLayerDelegate::paintContents) try to paint throttled content.
     DocumentLifecycle::AllowThrottlingScope allowThrottling(m_owningLayer.layoutObject()->document().lifecycle());
 #if ENABLE(ASSERT)
     // FIXME: once the state machine is ready, this can be removed and we can refer to that instead.
     if (Page* page = layoutObject()->frame()->page())
         page->setIsPainting(true);
 #endif
 
-    TRACE_EVENT1("devtools.timeline", "Paint", "data", InspectorPaintEvent::data(m_owningLayer.layoutObject(), LayoutRect(interestRect), graphicsLayer));
+    TRACE_EVENT1("devtools.timeline,rail", "Paint", "data", InspectorPaintEvent::data(m_owningLayer.layoutObject(), LayoutRect(interestRect), graphicsLayer));
 
     PaintLayerFlags paintLayerFlags = 0;
     if (graphicsLayerPaintingPhase & GraphicsLayerPaintBackground)
         paintLayerFlags |= PaintLayerPaintingCompositingBackgroundPhase;
     else
         paintLayerFlags |= PaintLayerPaintingSkipRootBackground;
     if (graphicsLayerPaintingPhase & GraphicsLayerPaintForeground)
         paintLayerFlags |= PaintLayerPaintingCompositingForegroundPhase;
     if (graphicsLayerPaintingPhase & GraphicsLayerPaintMask)
         paintLayerFlags |= PaintLayerPaintingCompositingMaskPhase;
@@ skipping 261 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink