Add RAIL tracing category to Chrome tracing.

ui/events/latency_info.cc

 // Copyright 2013 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 "ui/events/latency_info.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 101 matching lines @@
 void LatencyInfoTracedValue::AppendAsTraceFormat(std::string* out) const {
   std::string tmp;
   base::JSONWriter::Write(*value_, &tmp);
   *out += tmp;
 }
 
 LatencyInfoTracedValue::LatencyInfoTracedValue(base::Value* value)
     : value_(value) {
 }
 
-const char kTraceCategoriesForAsyncEvents[] = "benchmark,latencyInfo";
+const char kTraceCategoriesForAsyncEvents[] = "benchmark,latencyInfo,rail";
 
 struct LatencyInfoEnabledInitializer {
   LatencyInfoEnabledInitializer() :
       latency_info_enabled(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
           kTraceCategoriesForAsyncEvents)) {
   }
 
   const unsigned char* latency_info_enabled;
 };
 
@@ skipping 234 matching lines @@
 }
 
 bool LatencyInfo::AddInputCoordinate(const gfx::PointF& input_coordinate) {
   if (input_coordinates_size_ >= kMaxInputCoordinates)
     return false;
   input_coordinates_[input_coordinates_size_++] = input_coordinate;
   return true;
 }
 
 }  // namespace ui