Implement TransformFeedbackManager in GPU command buffer.

gpu/command_buffer/service/context_state.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.
 
 // This file contains the ContextState class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_CONTEXT_STATE_H_
 #define GPU_COMMAND_BUFFER_SERVICE_CONTEXT_STATE_H_
 
 #include <memory>
@@ skipping 11 matching lines @@
 namespace gles2 {
 
 class Buffer;
 class ErrorState;
 class ErrorStateClient;
 class FeatureInfo;
 class Framebuffer;
 class Logger;
 class Program;
 class Renderbuffer;
+class TransformFeedback;
 
 // State associated with each texture unit.
 struct GPU_EXPORT TextureUnit {
   TextureUnit();
   TextureUnit(const TextureUnit& other);
   ~TextureUnit();
 
   // The last target that was bound to this texture unit.
   GLenum bind_target;
 
@@ skipping 139 matching lines @@
   void RestoreAllTextureUnitBindings(const ContextState* prev_state) const;
   void RestoreActiveTextureUnitBinding(unsigned int target) const;
   void RestoreVertexAttribValues() const;
   void RestoreVertexAttribArrays(
       const scoped_refptr<VertexAttribManager> attrib_manager) const;
   void RestoreVertexAttribs() const;
   void RestoreBufferBindings() const;
   void RestoreGlobalState(const ContextState* prev_state) const;
   void RestoreProgramBindings() const;
   void RestoreRenderbufferBindings();
+  void RestoreTransformFeedbackBindings(const ContextState* prev_state);
   void RestoreTextureUnitBindings(
       GLuint unit, const ContextState* prev_state) const;
 
   // Helper for getting cached state.
   bool GetStateAsGLint(
       GLenum pname, GLint* params, GLsizei* num_written) const;
   bool GetStateAsGLfloat(
       GLenum pname, GLfloat* params, GLsizei* num_written) const;
   bool GetEnabled(GLenum cap) const;
 
@@ skipping 65 matching lines @@
   scoped_refptr<Buffer> bound_pixel_unpack_buffer;
   scoped_refptr<Buffer> bound_transform_feedback_buffer;
   scoped_refptr<Buffer> bound_uniform_buffer;
 
   // Which textures are bound to texture units through glActiveTexture.
   std::vector<TextureUnit> texture_units;
 
   // Which samplers are bound to each texture unit;
   std::vector<scoped_refptr<Sampler>> sampler_units;
 
+  // We create a transform feedback as the default one per ES3 enabled context
+  // instead of using GL's default one to make context switching easier.
+  // For other context, we will never change the default transform feedback's
+  // states, so we can just use the GL's default one.
+  scoped_refptr<TransformFeedback> default_transform_feedback;
+
+  scoped_refptr<TransformFeedback> bound_transform_feedback;
+
   // The values for each attrib.
   std::vector<Vec4> attrib_values;
 
   // Class that manages vertex attribs.
   scoped_refptr<VertexAttribManager> vertex_attrib_manager;
   scoped_refptr<VertexAttribManager> default_vertex_attrib_manager;
 
   // The program in use by glUseProgram
   scoped_refptr<Program> current_program;
 
@@ skipping 20 matching lines @@
 
   FeatureInfo* feature_info_;
   std::unique_ptr<ErrorState> error_state_;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_CONTEXT_STATE_H_