Simplify logic involving BackTexture.

gpu/command_buffer/service/texture_manager.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_TEXTURE_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_TEXTURE_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 616 matching lines @@
 
   void AddObserver() { num_observers_++; }
   void RemoveObserver() { num_observers_--; }
 
   const Texture* texture() const { return texture_; }
   Texture* texture() { return texture_; }
   GLuint client_id() const { return client_id_; }
   GLuint service_id() const { return texture_->service_id(); }
   GLint num_observers() const { return num_observers_; }
 
+  // When the TextureRef is destroyed, it will assume that the context has been
+  // lost, regardless of the state of the TextureManager.
+  void ForceContextLost();
+
  private:
   friend class base::RefCounted<TextureRef>;
   friend class Texture;
   friend class TextureManager;
 
   ~TextureRef();
   const TextureManager* manager() const { return manager_; }
   TextureManager* manager() { return manager_; }
   void reset_client_id() { client_id_ = 0; }
 
   TextureManager* manager_;
   Texture* texture_;
   GLuint client_id_;
   GLint num_observers_;
+  bool force_context_lost_;
 
   DISALLOW_COPY_AND_ASSIGN(TextureRef);
 };
 
 // Holds data that is per gles2_cmd_decoder, but is related to to the
 // TextureManager.
 struct DecoderTextureState {
   // total_texture_upload_time automatically initialized to 0 in default
   // constructor.
   explicit DecoderTextureState(const GpuDriverBugWorkarounds& workarounds)
@@ skipping 528 matching lines @@
  private:
   DecoderTextureState* texture_state_;
   base::TimeTicks begin_time_;
   DISALLOW_COPY_AND_ASSIGN(ScopedTextureUploadTimer);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_TEXTURE_MANAGER_H_