Windows docking should get triggered by pressing against the screen edge

ash/wm/dock/docked_window_layout_manager.h

Index: ash/wm/dock/docked_window_layout_manager.h
diff --git a/ash/wm/dock/docked_window_layout_manager.h b/ash/wm/dock/docked_window_layout_manager.h
index a3019aa7175c40381e52332781690242a04fc22f..d7aa68528813a82aa75018fae898c7e7fed711bb 100644
--- a/ash/wm/dock/docked_window_layout_manager.h
+++ b/ash/wm/dock/docked_window_layout_manager.h
@@ -61,6 +61,9 @@ class ASH_EXPORT DockedWindowLayoutManager
       public keyboard::KeyboardControllerObserver,
       public ash::ShelfLayoutManagerObserver {
  public:
+  // Maximum width of the docked windows area.
+  static const int kMaxDockWidth;
+
   explicit DockedWindowLayoutManager(aura::Window* dock_container);
   virtual ~DockedWindowLayoutManager();
 
@@ -102,6 +105,9 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Returns last known coordinates of |dragged_window_| after Relayout.
   const gfx::Rect dragged_bounds() const { return dragged_bounds_;}
 
+  // Returns true if currently dragged window is docked at the screen edge.
+  bool is_dragged_window_docked() const { return is_dragged_window_docked_; }
+
   // aura::LayoutManager:
   virtual void OnWindowResized() OVERRIDE;
   virtual void OnWindowAddedToLayout(aura::Window* child) OVERRIDE;
@@ -144,9 +150,6 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Minimum width of the docked windows area.
   static const int kMinDockWidth;
 
-  // Maximum width of the docked windows area.
-  static const int kMaxDockWidth;
-
   // Width of the gap between the docked windows and a workspace.
   static const int kMinDockGap;