Make scrollable viewport size no longer depend on clip layer.

cc/layers/scrollbar_layer_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_LAYERS_SCROLLBAR_LAYER_IMPL_H_
 #define CC_LAYERS_SCROLLBAR_LAYER_IMPL_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/input/scrollbar.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 27 matching lines @@
   int scroll_layer_id() const { return scroll_layer_id_; }
   void set_scroll_layer_id(int id) { scroll_layer_id_ = id; }
 
   ScrollbarOrientation Orientation() const;
   float CurrentPos() const;
   int Maximum() const;
 
   void set_thumb_thickness(int thumb_thickness) {
     thumb_thickness_ = thumb_thickness;
   }
+  int thumb_thickness() const { return thumb_thickness_; }
   void set_thumb_length(int thumb_length) {
     thumb_length_ = thumb_length;
   }
   void set_track_start(int track_start) {
     track_start_ = track_start;
   }
   void set_track_length(int track_length) {
     track_length_ = track_length;
   }
   void set_vertical_adjust(float vertical_adjust) {
     vertical_adjust_ = vertical_adjust;
   }
   void set_track_resource_id(ResourceProvider::ResourceId id) {
     track_resource_id_ = id;
   }
   void set_thumb_resource_id(ResourceProvider::ResourceId id) {
     thumb_resource_id_ = id;
   }
   void set_visible_to_total_length_ratio(float ratio) {
     visible_to_total_length_ratio_ = ratio;
   }
+  void set_is_overlay_scrollbar(bool is_overlay_scrollbar) {
+    is_overlay_scrollbar_ = is_overlay_scrollbar;
+  }
+  bool is_overlay_scrollbar() const { return is_overlay_scrollbar_; }
 
   void SetCurrentPos(float current_pos) { current_pos_ = current_pos; }
   void SetMaximum(int maximum) { maximum_ = maximum; }
 
   gfx::Rect ComputeThumbQuadRect() const;
 
  protected:
   ScrollbarLayerImpl(LayerTreeImpl* tree_impl,
                      int id,
                      ScrollbarOrientation orientation);
@@ skipping 15 matching lines @@
   ScrollbarOrientation orientation_;
 
   // Difference between the clip layer's height and the visible viewport
   // height (which may differ in the presence of top-controls hiding).
   float vertical_adjust_;
 
   float visible_to_total_length_ratio_;
 
   int scroll_layer_id_;
 
-  bool is_scrollable_area_active_;
-  bool is_scroll_view_scrollbar_;
-  bool enabled_;
-  bool is_custom_scrollbar_;
   bool is_overlay_scrollbar_;
 
   DISALLOW_COPY_AND_ASSIGN(ScrollbarLayerImpl);
 };
 
 }  // namespace cc
 #endif  // CC_LAYERS_SCROLLBAR_LAYER_IMPL_H_