Add a command-line flag to enable threaded GPU rasterization.

content/browser/gpu/compositor_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 "content/browser/gpu/compositor_util.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 274 matching lines @@
 bool IsForceGpuRasterizationEnabled() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
   if (!IsImplSidePaintingEnabled())
     return false;
 
   return command_line.HasSwitch(switches::kForceGpuRasterization);
 }
 
+bool IsThreadedGpuRasterizationEnabled() {
+  if (!IsImplSidePaintingEnabled())
+    return false;
+
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(switches::kDisableThreadedGpuRasterization))
+    return false;
+  if (command_line.HasSwitch(switches::kEnableThreadedGpuRasterization))
+    return true;
+
+  return false;
+}
+
 bool UseSurfacesEnabled() {
 #if defined(OS_ANDROID)
   return false;
 #else
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
   return command_line.HasSwitch(switches::kUseSurfaces);
 #endif
 }
@@ skipping 113 matching lines @@
     }
   }
   return problem_list;
 }
 
 std::vector<std::string> GetDriverBugWorkarounds() {
   return GpuDataManagerImpl::GetInstance()->GetDriverBugWorkarounds();
 }
 
 }  // namespace content