Hide pinch viewport scrollbars when near minimum scale.

cc/trees/layer_tree_impl.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 325 matching lines @@
       scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
       scoped_refptr<SyncedElasticOverscroll> elastic_overscroll);
   void ReleaseResourcesRecursive(LayerImpl* current);
   float ClampPageScaleFactorToLimits(float page_scale_factor) const;
   void PushPageScaleFactorAndLimits(const float* page_scale_factor,
                                     float min_page_scale_factor,
                                     float max_page_scale_factor);
   bool SetPageScaleFactorLimits(float min_page_scale_factor,
                                 float max_page_scale_factor);
   void DidUpdatePageScale();
+  void HideInnerViewportScrollbarsIfNearMinimumScale();
 
   LayerTreeHostImpl* layer_tree_host_impl_;
   int source_frame_number_;
   scoped_ptr<LayerImpl> root_layer_;
   HeadsUpDisplayLayerImpl* hud_layer_;
   LayerImpl* currently_scrolling_layer_;
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
   scoped_ptr<LayerScrollOffsetDelegateProxy>
       inner_viewport_scroll_delegate_proxy_;
   scoped_ptr<LayerScrollOffsetDelegateProxy>
@@ skipping 58 matching lines @@
 
   scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_