Add a base class of Texture for interfacing with the mailbox manager.

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 0c74c4b85057e97ac057420b9503bb45c1bb9ec4..8a1eb75189111cb3d7bd6db1d0ebe0d2824c0433 100644
--- a/gpu/command_buffer/service/texture_manager.h
+++ b/gpu/command_buffer/service/texture_manager.h
@@ -38,13 +38,40 @@ class ErrorState;
 class FeatureInfo;
 class FramebufferManager;
 class MailboxManager;
+class Texture;
 class TextureManager;
 class TextureRef;
 
+class GPU_EXPORT TextureBase {
+ public:
+  explicit TextureBase(GLuint service_id);
+  virtual ~TextureBase();
+
+  // The service side OpenGL id of the texture.
+  GLuint service_id() const { return service_id_; }
+
+  // Down-cast to other texture classes
+  virtual Texture* AsTexture();

[piman, 2016/09/07 17:38:31]

Will we ever use more than one derived type in a given MailboxManager? If not,
this is unnecessary and could be replaced with static casts.

[Geoff Lang, 2016/09/07 18:14:49]

No, each mailbox manager will only ever use one kind of texture object.  I can
fall back to static_casts, but I wasn't sure how comfortable you would be with
that more "unsafe" style.

Done.

+
+ protected:
+  // The id of the texture.
+  GLuint service_id_;
+
+  void DeleteFromMailboxManager();
+
+ private:
+  friend class MailboxManagerSync;
+  friend class MailboxManagerImpl;
+
+  void SetMailboxManager(MailboxManager* mailbox_manager);
+
+  MailboxManager* mailbox_manager_;
+};
+
 // Info about Textures currently in the system.
 // This class wraps a real GL texture, keeping track of its meta-data. It is
 // jointly owned by possibly multiple TextureRef.
-class GPU_EXPORT Texture {
+class GPU_EXPORT Texture final : public TextureBase {
  public:
   enum ImageState {
     // If an image is associated with the texture and image state is UNBOUND,
@@ -73,6 +100,8 @@ class GPU_EXPORT Texture {
 
   explicit Texture(GLuint service_id);
 
+  Texture* AsTexture() final;
+
   const SamplerState& sampler_state() const {
     return sampler_state_;
   }
@@ -141,11 +170,6 @@ class GPU_EXPORT Texture {
 
   bool CanRenderTo(const FeatureInfo* feature_info, GLint level) const;
 
-  // The service side OpenGL id of the texture.
-  GLuint service_id() const {
-    return service_id_;
-  }
-
   void SetServiceId(GLuint service_id) {
     DCHECK(service_id);
     DCHECK_EQ(owned_service_id_, service_id_);
@@ -289,7 +313,7 @@ class GPU_EXPORT Texture {
   friend class TextureRef;
   friend class TextureTestHelper;
 
-  ~Texture();
+  ~Texture() override;
   void AddTextureRef(TextureRef* ref);
   void RemoveTextureRef(TextureRef* ref, bool have_context);
   MemoryTypeTracker* GetMemTracker();
@@ -480,8 +504,6 @@ class GPU_EXPORT Texture {
       const FeatureInfo* feature_info,
       GLenum target, GLint level, std::string* signature) const;
 
-  void SetMailboxManager(MailboxManager* mailbox_manager);
-
   // Updates the unsafe textures count in all the managers referencing this
   // texture.
   void UpdateSafeToRenderFrom(bool cleared);
@@ -527,8 +549,6 @@ class GPU_EXPORT Texture {
   GLenum GetCompatibilitySwizzleForChannel(GLenum channel);
   void SetCompatibilitySwizzle(const CompatibilitySwizzle* swizzle);
 
-  MailboxManager* mailbox_manager_;
-
   // Info about each face and level of texture.
   std::vector<FaceInfo> face_infos_;
 
@@ -540,9 +560,6 @@ class GPU_EXPORT Texture {
   // one of refs_.
   TextureRef* memory_tracking_ref_;
 
-  // The id of the texture.
-  GLuint service_id_;
-
   // The id of the texture that we are responsible for deleting.  Normally, this
   // is the same as |service_id_|, unless a GLStreamTextureImage with its own
   // service id is bound. In that case the GLStreamTextureImage service id is