Add support for GL_CHROMIUM_pixel_transfer_buffer_object.

gpu/command_buffer/client/gles2_implementation.h

Index: gpu/command_buffer/client/gles2_implementation.h
diff --git a/gpu/command_buffer/client/gles2_implementation.h b/gpu/command_buffer/client/gles2_implementation.h
index 67d0c15236544773a7b9825a6955d8da952b6c46..acc4242c2a742fefafbc36e7a6e4ffd51103d024 100644
--- a/gpu/command_buffer/client/gles2_implementation.h
+++ b/gpu/command_buffer/client/gles2_implementation.h
@@ -15,6 +15,7 @@
 
 #include "../common/gles2_cmd_utils.h"
 #include "../common/scoped_ptr.h"
+#include "../client/buffer_tracker.h"
 #include "../client/ref_counted.h"
 #include "../client/gles2_cmd_helper.h"
 #include "../client/query_tracker.h"
@@ -519,6 +520,10 @@ class GLES2_IMPL_EXPORT GLES2Implementation {
   // The currently bound element array buffer.
   GLuint bound_element_array_buffer_id_;
 
+  // The currently bound pixel transfer buffers.
+  GLuint bound_pixel_pack_transfer_buffer_id_;
+  GLuint bound_pixel_unpack_transfer_buffer_id_;
+
   // GL names for the buffers used to emulate client side buffers.
   GLuint client_side_array_id_;
   GLuint client_side_element_array_id_;
@@ -560,6 +565,8 @@ class GLES2_IMPL_EXPORT GLES2Implementation {
   scoped_ptr<QueryTracker> query_tracker_;
   QueryTracker::Query* current_query_;
 
+  scoped_ptr<BufferTracker> buffer_tracker_;
+
   ErrorMessageCallback* error_message_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(GLES2Implementation);