ui: Add gfx::BufferUsage::SCANOUT_CPU_READ_WRITE.

gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.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 "gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 80 matching lines @@
       base::MakeUnique<base::SharedMemory>(handle.handle, false), handle.offset,
       handle.stride));
 }
 
 // static
 bool GpuMemoryBufferImplSharedMemory::IsUsageSupported(gfx::BufferUsage usage) {
   switch (usage) {
     case gfx::BufferUsage::GPU_READ:
     case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
     case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
+    case gfx::BufferUsage::SCANOUT_CPU_READ_WRITE:
       return true;
     case gfx::BufferUsage::SCANOUT:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 // static
 bool GpuMemoryBufferImplSharedMemory::IsConfigurationSupported(
@@ skipping 92 matching lines @@
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::SHARED_MEMORY_BUFFER;
   handle.id = id_;
   handle.offset = offset_;
   handle.stride = stride_;
   handle.handle = shared_memory_->handle();
   return handle;
 }
 
 }  // namespace gpu