gpu: Fix some context lost marking glitches+leaks and add UMA stats

gpu/command_buffer/service/context_group.h

 // 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.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_CONTEXT_GROUP_H_
 #define GPU_COMMAND_BUFFER_SERVICE_CONTEXT_GROUP_H_
 
 #include <string>
 #include <vector>
 #include "base/basictypes.h"
@@ skipping 148 matching lines @@
     return shader_manager_.get();
   }
 
   TransferBufferManagerInterface* transfer_buffer_manager() const {
     return transfer_buffer_manager_.get();
   }
 
   uint32 GetMemRepresented() const;
 
   // Loses all the context associated with this group.
-  void LoseContexts(GLenum reset_status);
+  void LoseContexts(error::ContextLostReason reason);
 
   // EXT_draw_buffer related states for backbuffer.
   GLenum draw_buffer() const {
     return draw_buffer_;
   }
   void set_draw_buffer(GLenum buf) {
     draw_buffer_ = buf;
   }
 
   bool GetBufferServiceId(GLuint client_id, GLuint* service_id) const;
@@ skipping 112 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(ContextGroup);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_CONTEXT_GROUP_H_