gpu: Empty swaps for surfaceless output surfaces.

gpu/command_buffer/common/capabilities.h

 // Copyright 2013 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_COMMON_CAPABILITIES_H_
 #define GPU_COMMAND_BUFFER_COMMON_CAPABILITIES_H_
 
 #include <stdint.h>
 
 #include "gpu/gpu_export.h"
@@ skipping 154 matching lines @@
   bool chromium_image_rgb_emulation = false;
 
   // When true, RGB framebuffer formats are unsupported. Emulate with RGBA to
   // work around this. See https://crbug.com/449150 for an example.
   bool emulate_rgb_buffer_with_rgba = false;
 
   // When true, is safe to convert a canvas from software to accelerated.
   // See https://crbug.com/710029.
   bool software_to_accelerated_canvas_upgrade = true;
 
+  // When true, non-empty post sub buffer calls are unsupported.
+  bool disable_non_empty_post_sub_buffers = false;

[jbauman, 2017/04/20 00:23:47]

Wouldn't an empty PostSubBuffers with a surfaceless compositor be essentially
equal to CommitOverlayPlanes? Maybe we should just be using that instead.

[reveman, 2017/04/20 18:21:35]

Almost. We still need to commit the primary plane and not just the overlays for
now. That can change in the future as it's not a requirement at the lowest
level, I think. I can look at that as a follow up but as we need this to be
merged into M58 I'd like to first land this SwapBuffers based approach.

+
   int major_version = 2;
   int minor_version = 0;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_CAPABILITIES_H_