Implement TransformFeedbackManager in GPU command buffer.

gpu/command_buffer/service/context_group.h

Index: gpu/command_buffer/service/context_group.h
diff --git a/gpu/command_buffer/service/context_group.h b/gpu/command_buffer/service/context_group.h
index e27dd68827334cc6dfb6c656ea302a98114c35b7..a385abd5bce3c3ac3abbd748d48afa9ebdc1a636 100644
--- a/gpu/command_buffer/service/context_group.h
+++ b/gpu/command_buffer/service/context_group.h
@@ -41,6 +41,7 @@ class ProgramManager;
 class SamplerManager;
 class ShaderManager;
 class TextureManager;
+class TransformFeedbackManager;
 class MemoryTracker;
 struct DisallowedFeatures;
 
@@ -191,6 +192,10 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
     return sampler_manager_.get();
   }
 
+  TransformFeedbackManager* transform_feedback_manager() const {
+    return transform_feedback_manager_.get();
+  }
+
   uint32_t GetMemRepresented() const;
 
   // Loses all the context associated with this group.
@@ -198,31 +203,6 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
 
   bool GetBufferServiceId(GLuint client_id, GLuint* service_id) const;
 
-  void AddTransformFeedbackId(GLuint client_id, GLuint service_id) {
-    transformfeedbacks_id_map_[client_id] = service_id;
-  }
-
-  bool GetTransformFeedbackServiceId(
-      GLuint client_id, GLuint* service_id) const {
-    if (client_id == 0) {
-      // Default one.
-      if (service_id)
-        *service_id = 0;
-      return true;
-    }
-    base::hash_map<GLuint, GLuint>::const_iterator iter =
-        transformfeedbacks_id_map_.find(client_id);
-    if (iter == transformfeedbacks_id_map_.end())
-      return false;
-    if (service_id)
-      *service_id = iter->second;
-    return true;
-  }
-
-  void RemoveTransformFeedbackId(GLuint client_id) {
-    transformfeedbacks_id_map_.erase(client_id);
-  }
-
   void AddSyncId(GLuint client_id, GLsync service_id) {
     syncs_id_map_[client_id] = service_id;
   }
@@ -299,12 +279,13 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
 
   std::unique_ptr<SamplerManager> sampler_manager_;
 
+  std::unique_ptr<TransformFeedbackManager> transform_feedback_manager_;

[piman, 2016/04/28 01:38:47]

So, actually, transform feedback objects are not shared across contexts, like
query objects, vertex array objects, and... framebuffer objects (oops - this was
left undefined in GLES2, but precised in GLES3). This is clarified in the
Appendix D.

So, the transform_feedback_manager_ should be in the GLES2DecoderImpl.
(separately from this patch, we should investigate moving framebuffer_manager_
to the decoder too, but that's trickier).

[Zhenyao Mo, 2016/04/29 21:07:54]

Done.

+
   scoped_refptr<FeatureInfo> feature_info_;
 
   std::vector<base::WeakPtr<gles2::GLES2Decoder> > decoders_;
 
   // Mappings from client side IDs to service side IDs.
-  base::hash_map<GLuint, GLuint> transformfeedbacks_id_map_;
   base::hash_map<GLuint, GLsync> syncs_id_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ContextGroup);