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

ui/gl/gl_surface_ozone.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 "ui/gl/gl_surface.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 552 matching lines @@
 
 bool GLSurfaceOzoneSurfacelessSurfaceImpl::CreatePixmaps() {
   if (!fbo_)
     return true;
   for (size_t i = 0; i < arraysize(textures_); i++) {
     scoped_refptr<ui::NativePixmap> pixmap =
         ui::OzonePlatform::GetInstance()
             ->GetSurfaceFactoryOzone()
             ->CreateNativePixmap(widget_, GetSize(),
                                  gfx::BufferFormat::BGRA_8888,
-                                 gfx::BufferUsage::GPU_READ_WRITE);
+                                 gfx::BufferUsage::SCANOUT);
     if (!pixmap)
       return false;
     scoped_refptr<GLImageOzoneNativePixmap> image =
         new GLImageOzoneNativePixmap(GetSize(), GL_BGRA_EXT);
     if (!image->Initialize(pixmap.get(), gfx::BufferFormat::BGRA_8888))
       return false;
     images_[i] = image;
     // Bind image to texture.
     ScopedTextureBinder binder(GL_TEXTURE_2D, textures_[i]);
     if (!images_[i]->BindTexImage(GL_TEXTURE_2D))
@@ skipping 130 matching lines @@
   }
 }
 
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay() {
   return ui::OzonePlatform::GetInstance()
       ->GetSurfaceFactoryOzone()
       ->GetNativeDisplay();
 }
 
 }  // namespace gfx