Fix viewport computation in Mac UC

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 1346 matching lines @@
 }
 
 void LayerTreeHostImpl::OnCanDrawStateChangedForTree() {
   client_->OnCanDrawStateChanged(CanDraw());
 }
 
 CompositorFrameMetadata LayerTreeHostImpl::MakeCompositorFrameMetadata() const {
   CompositorFrameMetadata metadata;
   metadata.device_scale_factor = device_scale_factor_;
   metadata.page_scale_factor = active_tree_->total_page_scale_factor();
-  metadata.viewport_size = active_tree_->ScrollableViewportSize();
+  metadata.scrollable_viewport_size = active_tree_->ScrollableViewportSize();
   metadata.root_layer_size = active_tree_->ScrollableSize();
   metadata.min_page_scale_factor = active_tree_->min_page_scale_factor();
   metadata.max_page_scale_factor = active_tree_->max_page_scale_factor();
   if (top_controls_manager_) {
     metadata.location_bar_offset =
         gfx::Vector2dF(0.f, top_controls_manager_->controls_top_offset());
     metadata.location_bar_content_translation =
         gfx::Vector2dF(0.f, top_controls_manager_->content_top_offset());
     metadata.overdraw_bottom_height = overdraw_bottom_height_;
   }
@@ skipping 1774 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