Add threaded compositing mode to field trial

content/public/common/content_constants.h

 // Copyright (c) 2012 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.
 
 // A handful of resource-like constants related to the Content application.
 
 #ifndef CONTENT_PUBLIC_COMMON_CONTENT_CONSTANTS_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_CONSTANTS_H_
 
 #include <stddef.h>         // For size_t
@@ skipping 35 matching lines @@
 extern const int kStatsMaxThreads;
 extern const int kStatsMaxCounters;
 
 // Most sequence numbers are used by a renderer when responding to a browser
 // request for histogram data.  This reserved number is used when a renderer
 // sends an unprovoked update, such as after a page has been loaded.  Using
 // this reserved constant avoids any chance of confusion with a response having
 // a browser-supplied sequence number.
 CONTENT_EXPORT extern const int kHistogramSynchronizerReservedSequenceNumber;
 
+CONTENT_EXPORT extern const char kGpuCompositingFieldTrialName[];
+CONTENT_EXPORT extern const char kGpuCompositingFieldTrialEnabledName[];
+CONTENT_EXPORT extern const char kGpuCompositingFieldTrialThreadEnabledName[];
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_CONSTANTS_H_