Explicitly resize inner viewport container layer on SetViewportSize

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 2094 matching lines @@
     return;
 
   if (pending_tree_)
     active_tree_->SetViewportSizeInvalid();
 
   device_viewport_size_ = device_viewport_size;
 
   UpdateInnerViewportContainerSize();
   client_->OnCanDrawStateChanged(CanDraw());
   SetFullRootLayerDamage();
+  active_tree_->set_needs_update_draw_properties();
 }
 
 void LayerTreeHostImpl::SetOverdrawBottomHeight(float overdraw_bottom_height) {
   if (overdraw_bottom_height == overdraw_bottom_height_)
     return;
   overdraw_bottom_height_ = overdraw_bottom_height;
 
   UpdateInnerViewportContainerSize();
   SetFullRootLayerDamage();
 }
@@ skipping 1117 matching lines @@
 }
 
 void LayerTreeHostImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
   std::vector<PictureLayerImpl*>::iterator it =
       std::find(picture_layers_.begin(), picture_layers_.end(), layer);
   DCHECK(it != picture_layers_.end());
   picture_layers_.erase(it);
 }
 
 }  // namespace cc