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

ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc

 // Copyright 2015 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/ozone/platform/drm/client_native_pixmap_factory_gbm.h"
 
 #include "ui/gfx/native_pixmap_handle_ozone.h"
 #include "ui/ozone/public/client_native_pixmap_factory.h"
 
 #if defined(USE_VGEM_MAP)
@@ skipping 30 matching lines @@
     // It's called in IO thread. We rely on clients for thread-safety.
     // Switching to an IPC message filter ensures thread-safety.
     DCHECK_LT(vgem_fd_.get(), 0);
     vgem_fd_ = device_fd.Pass();
 #endif
   }
   bool IsConfigurationSupported(gfx::BufferFormat format,
                                 gfx::BufferUsage usage) const override {
     switch (usage) {
       case gfx::BufferUsage::GPU_READ:
-      case gfx::BufferUsage::GPU_READ_WRITE:
+      case gfx::BufferUsage::SCANOUT:
         return format == gfx::BufferFormat::RGBA_8888 ||
                format == gfx::BufferFormat::BGRA_8888 ||
                format == gfx::BufferFormat::BGRX_8888;
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT: {
 #if defined(USE_VGEM_MAP)
         return vgem_fd_.is_valid() && format == gfx::BufferFormat::BGRA_8888;
 #else
         return false;
 #endif
@@ skipping 14 matching lines @@
 #if defined(USE_VGEM_MAP)
         // A valid |vgem_fd_| is required to acquire a VGEM bo. |vgem_fd_| is
         // set before a widget is created.
         DCHECK_GE(vgem_fd_.get(), 0);
         return ClientNativePixmapVgem::ImportFromDmabuf(
             vgem_fd_.get(), scoped_fd.get(), size, handle.stride);
 #endif
         NOTREACHED();
         return nullptr;
       case gfx::BufferUsage::GPU_READ:
-      case gfx::BufferUsage::GPU_READ_WRITE:
+      case gfx::BufferUsage::SCANOUT:
         return make_scoped_ptr<ClientNativePixmapGbm>(
             new ClientNativePixmapGbm);
     }
     NOTREACHED();
     return nullptr;
   }
 
  private:
 #if defined(USE_VGEM_MAP)
   base::ScopedFD vgem_fd_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ClientNativePixmapFactoryGbm);
 };
 
 ClientNativePixmapFactory* CreateClientNativePixmapFactoryGbm() {
   return new ClientNativePixmapFactoryGbm();
 }
 
 }  // namespace ui