Introduce bottom controls to CC and let it respond to scrolling

cc/trees/layer_tree_host.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 233 matching lines @@
   const LayerTreeDebugState& debug_state() const { return debug_state_; }
 
   bool has_gpu_rasterization_trigger() const {
     return has_gpu_rasterization_trigger_;
   }
   void SetHasGpuRasterizationTrigger(bool has_trigger);
 
   void SetViewportSize(const gfx::Size& device_viewport_size);
   void SetTopControlsHeight(float height, bool shrink);
   void SetTopControlsShownRatio(float ratio);
+  void setBottomControlHeight(float height);
 
   gfx::Size device_viewport_size() const { return device_viewport_size_; }
 
   void ApplyPageScaleDeltaFromImplSide(float page_scale_delta);
   void SetPageScaleFactorAndLimits(float page_scale_factor,
                                    float min_page_scale_factor,
                                    float max_page_scale_factor);
   float page_scale_factor() const { return page_scale_factor_; }
   gfx::Vector2dF elastic_overscroll() const { return elastic_overscroll_; }
 
@@ skipping 275 matching lines @@
 
   base::WeakPtr<InputHandler> input_handler_weak_ptr_;
 
   const LayerTreeSettings settings_;
   LayerTreeDebugState debug_state_;
 
   gfx::Size device_viewport_size_;
   bool top_controls_shrink_blink_size_;
   float top_controls_height_;
   float top_controls_shown_ratio_;
+  float bottom_controls_height_;
   float device_scale_factor_;
   float painted_device_scale_factor_;
 
   bool visible_;
 
   float page_scale_factor_;
   float min_page_scale_factor_;
   float max_page_scale_factor_;
   gfx::Vector2dF elastic_overscroll_;
   bool has_gpu_rasterization_trigger_;
@@ skipping 47 matching lines @@
 
   uint32_t surface_id_namespace_;
   uint32_t next_surface_sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_