Always enable FCM on Windows.

chrome/browser/gpu/chrome_gpu_util.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 "chrome/browser/gpu/chrome_gpu_util.h"
 
 #include "base/command_line.h"
 #if defined(OS_MACOSX)
 #include "base/mac/mac_util.h"
 #endif
@@ skipping 22 matching lines @@
   if (trial)
     trial->Disable();
 }
 
 bool ShouldRunCompositingFieldTrial() {
 // Enable the field trial only on desktop OS's.
 #if !(defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX))
   return false;
 #endif
 
-// Necessary for linux_chromeos build since it defines both OS_LINUX
-// and OS_CHROMEOS.
-#if defined(OS_CHROMEOS)
-  return false;

[gab, 2013/08/15 20:07:49]

This didn't make sense as CHROME_OS always returns true in
IsThreadedCompositingEnabled() et al.

-#endif
-
-#if defined(OS_WIN)
-  // Don't run the trial on Windows XP.
-  if (base::win::GetVersion() < base::win::VERSION_VISTA)
-    return false;

[gab, 2013/08/15 20:07:49]

This is now applied by the blacklist on the bots, no need to special case for
tests.

-#endif
-
-#if defined(OS_MACOSX)
-  // Browser and content shell tests hang on 10.7 when the Apple software
-  // renderer is used. These tests ignore the blacklist (which disables
-  // compositing both on 10.7 and when the Apple software renderer is used)
-  // by specifying the kSkipGpuDataLoading switch, so disable forced
-  // compositing here based on the switch and OS version.
-  // http://crbug.com/230931
-  if (base::mac::IsOSLion() &&
-      CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSkipGpuDataLoading)) {
-    return false;

[gab, 2013/08/15 20:07:49]

This is now applied by the blacklist on the bots, no need to special case for
tests.

-  }
-#endif
-
   // Don't activate the field trial if force-compositing-mode has been
   // explicitly disabled from the command line.
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableForceCompositingMode) ||
       CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableAcceleratedCompositing))
     return false;
 
   return true;
 }
@@ skipping 44 matching lines @@
 
   bool force_compositing = (trial->group() == force_compositing_group);
   bool thread = (trial->group() == thread_group);
   UMA_HISTOGRAM_BOOLEAN("GPU.InForceCompositingModeFieldTrial",
                         force_compositing);
   UMA_HISTOGRAM_BOOLEAN("GPU.InCompositorThreadFieldTrial", thread);
 }
 
 }  // namespace gpu_util