[Command buffer]: we can call blitFramebuffer directly from multi-sampled srgb image to srgb image

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 7691 matching lines @@
       return;
     }
   }
 
   bool enable_srgb =
       (read_buffer_has_srgb || draw_buffers_has_srgb) &&
       ((mask & GL_COLOR_BUFFER_BIT) != 0);
   bool encode_srgb_only =
       (draw_buffers_has_srgb && !read_buffer_has_srgb) &&
       ((mask & GL_COLOR_BUFFER_BIT) != 0);
-  // TODO(yunchao) Need to revisit here if the read buffer is a multi-sampled
-  // renderbuffer.

[piman, 2016/09/20 20:55:25]

As discussed in that other CL, there is just one more check to add, which is
that the destination must not be multisampled.

   if (!enable_srgb ||
       read_buffer_samples > 0 ||
       !feature_info_->feature_flags().desktop_srgb_support ||
       gl_version_info().IsAtLeastGL(4, 4) ||
       (gl_version_info().IsAtLeastGL(4, 2) && encode_srgb_only)) {
     if (enable_srgb && gl_version_info().IsAtLeastGL(4, 2)) {
       state_.EnableDisableFramebufferSRGB(enable_srgb);
     }
 
     // TODO(yunchao) Need to revisit here. In GLES spec, blitFramebuffer
@@ skipping 10351 matching lines @@
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu