Replaced is_null() with is_valid in SurfaceId and related classes.

ui/android/delegated_frame_host_android.cc

 // Copyright 2016 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/android/delegated_frame_host_android.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "cc/layers/solid_color_layer.h"
 #include "cc/layers/surface_layer.h"
@@ skipping 208 matching lines @@
 void DelegatedFrameHostAndroid::UpdateContainerSizeinDIP(
     const gfx::Size& size_in_dip) {
   container_size_in_dip_ = size_in_dip;
   background_layer_->SetBounds(gfx::ConvertSizeToPixel(
       gfx::DeviceDisplayInfo().GetDIPScale(), container_size_in_dip_));
   UpdateBackgroundLayer();
 }
 
 void DelegatedFrameHostAndroid::RegisterFrameSinkHierarchy(
     const cc::FrameSinkId& parent_id) {
-  if (!registered_parent_frame_sink_id_.is_null())
+  if (registered_parent_frame_sink_id_.is_valid())
     UnregisterFrameSinkHierarchy();
   registered_parent_frame_sink_id_ = parent_id;
   surface_manager_->RegisterSurfaceFactoryClient(frame_sink_id_, this);
   surface_manager_->RegisterFrameSinkHierarchy(parent_id, frame_sink_id_);
 }
 
 void DelegatedFrameHostAndroid::UnregisterFrameSinkHierarchy() {
-  if (registered_parent_frame_sink_id_.is_null())
+  if (!registered_parent_frame_sink_id_.is_valid())
     return;
   surface_manager_->UnregisterSurfaceFactoryClient(frame_sink_id_);
   surface_manager_->UnregisterFrameSinkHierarchy(
       registered_parent_frame_sink_id_, frame_sink_id_);
   registered_parent_frame_sink_id_ = cc::FrameSinkId();
 }
 
 void DelegatedFrameHostAndroid::ReturnResources(
     const cc::ReturnedResourceArray& resources) {
   return_resources_callback_.Run(resources);
@@ skipping 20 matching lines @@
         content_size_in_dip.width() < container_size_in_dip_.width() ||
         content_size_in_dip.height() < container_size_in_dip_.height();
   } else {
     background_is_drawable = true;
   }
 
   background_layer_->SetIsDrawable(background_is_drawable);
 }
 
 }  // namespace ui