Introduce bottom controls to CC and let it respond to scrolling

content/browser/android/content_view_core_impl.h

Index: content/browser/android/content_view_core_impl.h
diff --git a/content/browser/android/content_view_core_impl.h b/content/browser/android/content_view_core_impl.h
index 0cc3c7e22693bbd012f6306331ae2cd54b329484..81b00e174c3dd3c8d0bf3d2e7d21083ea5d81789 100644
--- a/content/browser/android/content_view_core_impl.h
+++ b/content/browser/android/content_view_core_impl.h
@@ -323,8 +323,10 @@ class ContentViewCoreImpl : public ContentViewCore,
                        const gfx::Vector2dF& page_scale_factor_limits,
                        const gfx::SizeF& content_size,
                        const gfx::SizeF& viewport_size,
-                       const gfx::Vector2dF& controls_offset,
-                       const gfx::Vector2dF& content_offset,
+                       const gfx::Vector2dF& top_controls_height,
+                       const float top_controls_shown_ratio,
+                       const gfx::Vector2dF& bottom_controls_height,
+                       const float bottom_controls_shown_ratio,
                        bool is_mobile_optimized_hint,
                        const gfx::SelectionBound& selection_start);
 
@@ -390,6 +392,7 @@ class ContentViewCoreImpl : public ContentViewCore,
   gfx::Size GetViewportSizeDip() const;
   bool DoTopControlsShrinkBlinkSize() const;
   float GetTopControlsHeightDip() const;
+  float GetBottomControlsHeightDip() const;
 
   void AttachLayer(scoped_refptr<cc::Layer> layer);
   void RemoveLayer(scoped_refptr<cc::Layer> layer);
@@ -434,6 +437,7 @@ class ContentViewCoreImpl : public ContentViewCore,
 
   gfx::Size GetViewportSizePix() const;
   int GetTopControlsHeightPix() const;
+  int GetBottomControlsHeightPix() const;
 
   void SendGestureEvent(const blink::WebGestureEvent& event);