ui: Revert gfx::BufferUsage::SCANOUT to gfx::BufferUsage::GPU_READ_WRITE change.

mojo/gles2/command_buffer_client_impl.cc

 // Copyright 2014 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 "mojo/gles2/command_buffer_client_impl.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/process/process_handle.h"
@@ skipping 303 matching lines @@
 }
 
 int32_t CommandBufferClientImpl::CreateGpuMemoryBufferImage(
     size_t width,
     size_t height,
     unsigned internalformat,
     unsigned usage) {
   scoped_ptr<gfx::GpuMemoryBuffer> buffer(mus::MojoGpuMemoryBufferImpl::Create(
       gfx::Size(static_cast<int>(width), static_cast<int>(height)),
       gpu::ImageFactory::DefaultBufferFormatForImageFormat(internalformat),
-      gfx::BufferUsage::GPU_READ_WRITE));
+      gfx::BufferUsage::SCANOUT));
   if (!buffer)
     return -1;
 
   return CreateImage(buffer->AsClientBuffer(), width, height, internalformat);
 }
 
 uint32_t CommandBufferClientImpl::InsertSyncPoint() {
   command_buffer_->InsertSyncPoint(true);
   return sync_point_client_impl_->WaitForInsertSyncPoint();
 }
@@ skipping 98 matching lines @@
   // TODO(dyen)
 }
 
 bool CommandBufferClientImpl::CanWaitUnverifiedSyncToken(
     const gpu::SyncToken* sync_token) {
   // All sync tokens must be flushed before being waited on.
   return false;
 }
 
 }  // namespace gles2