Implement client side PBOs for glReadPixel

gpu/command_buffer/client/gles2_implementation.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.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_H_
 #define GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_H_
 
 #include <GLES2/gl2.h>
 
 #include <map>
@@ skipping 464 matching lines @@
 
   IdHandlerInterface* GetIdHandler(int id_namespace) const;
 
   void FinishHelper();
 
   // Asserts that the context is lost.
   // NOTE: This is an expensive call and should only be called
   // for error checking.
   bool MustBeContextLost();
 
+  bool GetBoundPixelTransferBuffer(
+      GLenum target, const char* function_name, GLuint* buffer_id);
   BufferTracker::Buffer* GetBoundPixelUnpackTransferBufferIfValid(
+      GLuint buffer_id,
       const char* function_name, GLuint offset, GLsizei size);
 
   const std::string& GetLogPrefix() const;
 
 #if defined(GL_CLIENT_FAIL_GL_ERRORS)
   void CheckGLError();
   void FailGLError(GLenum error);
 #else
   void CheckGLError() { }
   void FailGLError(GLenum /* error */) { }
@@ skipping 44 matching lines @@
   GLuint bound_framebuffer_;
   GLuint bound_read_framebuffer_;
   GLuint bound_renderbuffer_;
 
   // The program in use by glUseProgram
   GLuint current_program_;
 
   // The currently bound array buffer.
   GLuint bound_array_buffer_id_;
 
-  // The currently bound pixel transfer buffer.
+  // The currently bound pixel transfer buffers.
+  GLuint bound_pixel_pack_transfer_buffer_id_;
   GLuint bound_pixel_unpack_transfer_buffer_id_;
 
   // Client side management for vertex array objects. Needed to correctly
   // track client side arrays.
   scoped_ptr<VertexArrayObjectManager> vertex_array_object_manager_;
 
   GLuint reserved_ids_[2];
 
   // Current GL error bits.
   uint32 error_bits_;
@@ skipping 65 matching lines @@
 
 inline bool GLES2Implementation::GetTexParameterivHelper(
     GLenum /* target */, GLenum /* pname */, GLint* /* params */) {
   return false;
 }
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_H_