Add field trial for enabling Stage3D in XP

content/public/common/content_constants.cc

 // 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.
 
 #include "content/public/common/content_constants.h"
 namespace content {
 
 const FilePath::CharType kAppCacheDirname[] =
     FILE_PATH_LITERAL("Application Cache");
 const FilePath::CharType kPepperDataDirname[] =
@@ skipping 23 matching lines @@
 
 const int kStatsMaxThreads = 32;
 const int kStatsMaxCounters = 3000;
 
 const int kHistogramSynchronizerReservedSequenceNumber = 0;
 
 const char kGpuCompositingFieldTrialName[] = "ForceCompositingMode";
 const char kGpuCompositingFieldTrialForceCompositingEnabledName[] = "enabled";
 const char kGpuCompositingFieldTrialThreadEnabledName[] = "thread";
 
+const char kStage3DFieldTrialName[] = "EnableStage3D";
+const char kStage3DFieldTrialBlacklistedName[] = "blacklisted";
+const char kStage3DFieldTrialEnabledName[] = "enabled";
+
 }  // namespace content