Add a flag to allow renderer to use software compositor when GL compositor doesn't work.

content/browser/gpu/gpu_data_manager_impl_private.h

 // Copyright (c) 2013 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.
 
 #ifndef CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_PRIVATE_H_
 #define CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_PRIVATE_H_
 
 #include <list>
 #include <map>
 #include <set>
@@ skipping 226 matching lines @@
   DomainBlockMap blocked_domains_;
   mutable std::list<base::Time> timestamps_of_gpu_resets_;
   bool domain_blocking_enabled_;
 
   GpuDataManagerImpl* owner_;
 
   unsigned int display_count_;
 
   bool gpu_process_accessible_;
 
+  bool use_software_compositor_;
+
   DISALLOW_COPY_AND_ASSIGN(GpuDataManagerImplPrivate);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_PRIVATE_H_