[ash-md] Erases the pre-MD code path for Overview Mode

ash/common/wm/overview/window_grid.h

Index: ash/common/wm/overview/window_grid.h
diff --git a/ash/common/wm/overview/window_grid.h b/ash/common/wm/overview/window_grid.h
index 587bd9e37d048246216fa6eb0a0534261cf641d5..a85b982078b51459ad88f2449938b6e43bb6ddc4 100644
--- a/ash/common/wm/overview/window_grid.h
+++ b/ash/common/wm/overview/window_grid.h
@@ -75,10 +75,6 @@ class ASH_EXPORT WindowGrid : public WmWindowObserver {
   // row height which is equivalent assuming fixed height), balanced rows and
   // minimal wasted space.
   // Optionally animates the windows to their targets when |animate| is true.
-  void PositionWindowsMD(bool animate);
-
-  // Positions all the windows in the grid.
-  // Optionally animates the windows to their targets when |animate| is true.
   void PositionWindows(bool animate);
 
   // Updates |selected_index_| according to the specified |direction| and calls
@@ -161,10 +157,6 @@ class ASH_EXPORT WindowGrid : public WmWindowObserver {
                               int* min_right,
                               int* max_right);
 
-  // Sets up WindowSelectorItem to use masks or shapes based on command flags.
-  // TODO(varkha): remove this in the next patch and use shapes but not masks.
-  void PrepareForUsingMasksOrShapes(size_t windows_count) const;
-
   // Root window the grid is in.
   WmWindow* root_window_;