Refactors DockedWindowLayoutManager in terms of ash/wm/common

ash/shelf/shelf_constants.h

Index: ash/shelf/shelf_constants.h
diff --git a/ash/shelf/shelf_constants.h b/ash/shelf/shelf_constants.h
index 0ff82802bb2acaf159bedb85b676d169ace96930..d7f0825b7394263afdec8f6f8952ef8c6e7f7a03 100644
--- a/ash/shelf/shelf_constants.h
+++ b/ash/shelf/shelf_constants.h
@@ -9,9 +9,6 @@
 
 namespace ash {
 
-// Max alpha of the shelf background.
-ASH_EXPORT extern const int kShelfBackgroundAlpha;
-
 // Invalid image resource id used for ShelfItemDetails.
 extern const int kInvalidImageResourceID;
 
@@ -26,9 +23,6 @@ ASH_EXPORT extern const int kShelfButtonSpacing;
 // Size allocated for each button on the shelf.
 ASH_EXPORT extern const int kShelfButtonSize;
 
-// Animation duration for switching black shelf and dock background on and off.
-ASH_EXPORT extern const int kTimeToSwitchBackgroundMs;
-
 // The direction of the focus cycling.
 enum CycleDirection {
   CYCLE_FORWARD,