Add RAIL tracing category to Chrome tracing.

third_party/WebKit/Source/core/paint/FramePainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/FramePainter.h"
 
 #include "core/editing/markers/DocumentMarkerController.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/frame/FrameView.h"
 #include "core/inspector/InspectorInstrumentation.h"
@@ skipping 91 matching lines @@
     if (!layoutView) {
         DLOG(ERROR) << "called FramePainter::paint with nil layoutObject";
         return;
     }
 
     frameView().checkDoesNotNeedLayout();
     // TODO(wangxianzhu): The following check should be stricter, but currently this is blocked
     // by the svg root issue (crbug.com/442939).
     ASSERT(document->lifecycle().state() >= DocumentLifecycle::CompositingClean);
 
-    TRACE_EVENT1("devtools.timeline", "Paint", "data", InspectorPaintEvent::data(layoutView, LayoutRect(rect), 0));
+    TRACE_EVENT1("devtools.timeline,rail", "Paint", "data", InspectorPaintEvent::data(layoutView, LayoutRect(rect), 0));
 
     bool isTopLevelPainter = !s_inPaintContents;
     s_inPaintContents = true;
 
     FontCachePurgePreventer fontCachePurgePreventer;
 
     // TODO(jchaffraix): GlobalPaintFlags should be const during a paint
     // phase. Thus we should set this flag upfront (crbug.com/510280).
     GlobalPaintFlags localPaintFlags = globalPaintFlags;
     if (document->printing())
@@ skipping 71 matching lines @@
     bar.paint(context, CullRect(rect));
 }
 
 const FrameView& FramePainter::frameView()
 {
     ASSERT(m_frameView);
     return *m_frameView;
 }
 
 } // namespace blink