Add reference-counting for mailbox textures.

gpu/command_buffer/service/texture_manager.h

Index: gpu/command_buffer/service/texture_manager.h
diff --git a/gpu/command_buffer/service/texture_manager.h b/gpu/command_buffer/service/texture_manager.h
index 976c198029693865e12730f26bee4a4425b5019d..06e7fd75601d86783ba62d81c191eea9b8cfbb19 100644
--- a/gpu/command_buffer/service/texture_manager.h
+++ b/gpu/command_buffer/service/texture_manager.h
@@ -14,6 +14,7 @@
 #include "base/memory/ref_counted.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/memory_tracking.h"
+#include "gpu/command_buffer/service/texture_definition.h"
 #include "gpu/gpu_export.h"
 #include "ui/gl/async_pixel_transfer_delegate.h"
 #include "ui/gl/gl_image.h"
@@ -24,11 +25,11 @@ namespace gles2 {
 class GLES2Decoder;
 class Display;
 class FeatureInfo;
-class TextureDefinition;
 class TextureManager;
 
 // Info about Textures currently in the system.
-class GPU_EXPORT Texture : public base::RefCounted<Texture> {
+class GPU_EXPORT Texture : public base::RefCounted<Texture>,
+                           private TextureDefinition::Client {
  public:
   Texture(TextureManager* manager, GLuint service_id);
 
@@ -290,6 +291,9 @@ class GPU_EXPORT Texture : public base::RefCounted<Texture> {
       const FeatureInfo* feature_info,
       GLenum target, GLint level, std::string* signature) const;
 
+  virtual void StartUsingSharedTexture(TextureDefinition* definition) OVERRIDE;
+  virtual bool StopUsingSharedTexture(bool have_context) OVERRIDE;
+
   // Info about each face and level of texture.
   std::vector<std::vector<LevelInfo> > level_infos_;
 
@@ -353,6 +357,9 @@ class GPU_EXPORT Texture : public base::RefCounted<Texture> {
   // Size in bytes this texture is assumed to take in memory.
   uint32 estimated_size_;
 
+  // A reference to a shared texture, keeping it from being deleted.
+  TextureDefinition* shared_texture_;
+
   DISALLOW_COPY_AND_ASSIGN(Texture);
 };