Move even more from WmShell to Shell

ash/common/wm/window_positioner.h

Index: ash/common/wm/window_positioner.h
diff --git a/ash/common/wm/window_positioner.h b/ash/common/wm/window_positioner.h
index 85cdfd614278e3b950bcb4a8bb4ed4b012087c0f..285f881eb53a11181238e3a79f261eda4b192e8a 100644
--- a/ash/common/wm/window_positioner.h
+++ b/ash/common/wm/window_positioner.h
@@ -19,7 +19,6 @@ class Rect;
 
 namespace ash {
 
-class WmShell;
 class WmWindow;
 
 namespace test {
@@ -73,7 +72,7 @@ class ASH_EXPORT WindowPositioner {
   // rearrange accordingly.
   static void RearrangeVisibleWindowOnShow(WmWindow* added_window);
 
-  explicit WindowPositioner(WmShell* shell);
+  WindowPositioner();
   ~WindowPositioner();
 
   // Find a suitable screen position for a popup window and return it. The
@@ -108,8 +107,6 @@ class ASH_EXPORT WindowPositioner {
   // Constant exposed for unittest.
   static const int kMinimumWindowOffset;
 
-  WmShell* shell_;
-
   // The offset in X and Y for the next popup which opens.
   int pop_position_offset_increment_x;
   int pop_position_offset_increment_y;