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

content/common/gpu/client/gpu_memory_buffer_impl_io_surface.cc

 // 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.
 
 #include "content/common/gpu/client/gpu_memory_buffer_impl_io_surface.h"
 
 #include "base/logging.h"
 #include "content/common/gpu/gpu_memory_buffer_factory_io_surface.h"
 #include "content/common/mac/io_surface_manager.h"
 #include "ui/gfx/buffer_format_util.h"
 
 namespace content {
 namespace {
 
 uint32_t LockFlags(gfx::BufferUsage usage) {
   switch (usage) {
     case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       return kIOSurfaceLockAvoidSync;
     case gfx::BufferUsage::GPU_READ:
-    case gfx::BufferUsage::GPU_READ_WRITE:
+    case gfx::BufferUsage::SCANOUT:
     case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
       return 0;
   }
   NOTREACHED();
   return 0;
 }
 
 void FreeIOSurfaceForTesting(gfx::GpuMemoryBufferId id) {
   IOSurfaceManager::GetInstance()->UnregisterIOSurface(id, 0);
 }
@@ skipping 84 matching lines @@
 }
 
 gfx::GpuMemoryBufferHandle GpuMemoryBufferImplIOSurface::GetHandle() const {
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::IO_SURFACE_BUFFER;
   handle.id = id_;
   return handle;
 }
 
 }  // namespace content