cc: Fix R_8 GpuMemoryBuffers

cc/resources/resource_provider.cc

 // Copyright 2012 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 1484 matching lines @@
     return;
   resource->allocated = true;
   GLES2Interface* gl = ContextGL();
   gfx::Size& size = resource->size;
   ResourceFormat format = resource->format;
   gl->BindTexture(resource->target, resource->gl_id);
   if (use_gpu_memory_buffer_resources_) {
     resource->gpu_memory_buffer =
         gpu_memory_buffer_manager_->AllocateGpuMemoryBuffer(
                                       size, BufferFormat(format),
-                                      gfx::BufferUsage::SCANOUT)
+                                      gfx::BufferUsage::GPU_READ_CPU_READ_WRITE)
             .release();
     LazyCreateImage(resource);
     resource->dirty_image = true;
     resource->is_overlay_candidate = true;
   } else if (use_texture_storage_ext_ &&
              IsFormatSupportedForStorage(format, use_texture_format_bgra_) &&
              (resource->hint & TEXTURE_HINT_IMMUTABLE)) {
     GLenum storage_format = TextureToStorageFormat(format);
     gl->TexStorage2DEXT(resource->target, 1, storage_format, size.width(),
                         size.height());
@@ skipping 135 matching lines @@
       const int kImportance = 2;
       pmd->CreateSharedGlobalAllocatorDump(guid);
       pmd->AddOwnershipEdge(dump->guid(), guid, kImportance);
     }
   }
 
   return true;
 }
 
 }  // namespace cc