Expose FS show/hide thresholds to Command Line

cc/top_controls_manager.h

Index: cc/top_controls_manager.h
diff --git a/cc/top_controls_manager.h b/cc/top_controls_manager.h
index d08031ed45242b52c09a725fe05dff50e1d9607e..bdfa5895374a8442e69f3ea4a9e9630105ff1946 100644
--- a/cc/top_controls_manager.h
+++ b/cc/top_controls_manager.h
@@ -30,8 +30,11 @@ class CC_EXPORT TopControlsManager {
     HIDING_CONTROLS
   };
 
-  static scoped_ptr<TopControlsManager> Create(TopControlsManagerClient* client,
-                                               float top_controls_height);
+  static scoped_ptr<TopControlsManager> Create(
+      TopControlsManagerClient* client,
+      float top_controls_height,
+      float top_controls_show_threshold,
+      float top_controls_hide_threshold);
   virtual ~TopControlsManager();
 
   float controls_top_offset() { return controls_top_offset_; }
@@ -49,7 +52,9 @@ class CC_EXPORT TopControlsManager {
 
  protected:
   TopControlsManager(TopControlsManagerClient* client,
-                     float top_controls_height);
+                     float top_controls_height,
+                     float top_controls_show_threshold,
+                     float top_controls_hide_threshold);
 
  private:
   gfx::Vector2dF ScrollInternal(const gfx::Vector2dF pending_delta);
@@ -70,6 +75,15 @@ class CC_EXPORT TopControlsManager {
   float top_controls_height_;
   float previous_root_scroll_offset_;
   float scroll_start_offset_;
+  float current_scroll_delta_;
+
+  // The height of the visible top control such that it must be shown when
+  // the user stops the scroll.
+  float top_controls_show_height_;
+
+  // The height of the visible top control such that it must be hidden when
+  // the user stops the scroll.
+  float top_controls_hide_height_;
 
   DISALLOW_COPY_AND_ASSIGN(TopControlsManager);
 };