Disable threaded compositing field trial on mac and linux

chrome/browser/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_util.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
@@ skipping 202 matching lines @@
     // default (mac and windows only).
 #if defined(OS_WIN) || defined(OS_MACOSX)
     force_compositing_mode_probability = 3;
 #endif
   } else if (channel == chrome::VersionInfo::CHANNEL_DEV ||
              channel == chrome::VersionInfo::CHANNEL_CANARY) {
     // Dev and Canary channels: force-compositing-mode and
     // threaded-compositing on with 1/3 probability each.
     force_compositing_mode_probability = 1;
 
+#if defined(OS_MACOSX) || defined(OS_LINUX)
+    // Threaded compositing mode isn't feature complete on mac or linux yet:
+    // http://crbug.com/133602 for mac
+    // http://crbug.com/140866 for linux
+    threaded_compositing_probability = 0;
+#else
     if (!CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kDisableThreadedCompositing))
         threaded_compositing_probability = 1;
+#endif
   }
 
+
   int force_compositing_group = trial->AppendGroup(
       content::kGpuCompositingFieldTrialForceCompositingEnabledName,
       force_compositing_mode_probability);
   int thread_group = trial->AppendGroup(
       content::kGpuCompositingFieldTrialThreadEnabledName,
       threaded_compositing_probability);
 
   bool force_compositing = (trial->group() == force_compositing_group);
   bool thread = (trial->group() == thread_group);
   UMA_HISTOGRAM_BOOLEAN("GPU.InForceCompositingModeFieldTrial",
@@ skipping 376 matching lines @@
         kGpuBlacklistFeatureHistogramNamesWin[i],
         1, kNumWinSubVersions * kGpuFeatureNumStatus,
         kNumWinSubVersions * kGpuFeatureNumStatus + 1,
         base::Histogram::kUmaTargetedHistogramFlag);
     histogram_pointer->Add(GetGpuBlacklistHistogramValueWin(value));
 #endif
   }
 }
 
 }  // namespace gpu_util;