Add reference-counting for mailbox textures.

gpu/command_buffer/service/texture_definition.h

Index: gpu/command_buffer/service/texture_definition.h
diff --git a/gpu/command_buffer/service/texture_definition.h b/gpu/command_buffer/service/texture_definition.h
index 7f7d3cdefea8fcd2eca790e4757acc3553e61ab4..9b33b587dbedb4e5b6eaf65fd564ba847faa50fe 100644
--- a/gpu/command_buffer/service/texture_definition.h
+++ b/gpu/command_buffer/service/texture_definition.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/callback.h"
+#include "base/memory/ref_counted.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/gpu_export.h"
 
@@ -17,7 +18,8 @@ namespace gles2 {
 // A saved definition of a texture that still exists in the underlying
 // GLShareGroup and can be used to redefine a client visible texture in any
 // context using the same GLShareGroup with the corresponding service ID.
-class GPU_EXPORT TextureDefinition {
+class GPU_EXPORT TextureDefinition :
+    public base::RefCounted<TextureDefinition> {
  public:
   struct GPU_EXPORT LevelInfo {
     LevelInfo(GLenum target,
@@ -57,11 +59,16 @@ class GPU_EXPORT TextureDefinition {
                     const LevelInfos& level_infos);
   ~TextureDefinition();
 
+  void SetDestroyCallback(const DestroyCallback& callback) {
+    destroy_callback_ = callback;
+  }
+
   GLenum target() const {
     return target_;
   }
 
   GLuint ReleaseServiceId();
+  GLuint service_id() const { return service_id_; }
   GLenum min_filter() const { return min_filter_; }
   GLenum mag_filter() const { return mag_filter_; }
   GLenum wrap_s() const { return wrap_s_; }
@@ -84,6 +91,7 @@ class GPU_EXPORT TextureDefinition {
   GLenum usage_;
   bool immutable_;
   std::vector<std::vector<LevelInfo> > level_infos_;
+  DestroyCallback destroy_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(TextureDefinition);
 };