Adds WmWindow and converts WindowState to use it

ash/wm/window_util.h

Index: ash/wm/window_util.h
diff --git a/ash/wm/window_util.h b/ash/wm/window_util.h
index e1240ae22d46d160ba8dc48dd012e555d38890ed..d8f861bfba3cd56f8b8b00f9e95ab526323bfbc0 100644
--- a/ash/wm/window_util.h
+++ b/ash/wm/window_util.h
@@ -29,6 +29,8 @@ const int kMinimumOnScreenArea = 25;
 
 namespace wm {
 
+class WmWindow;
+
 // Utility functions for window activation.
 ASH_EXPORT void ActivateWindow(aura::Window* window);
 ASH_EXPORT void DeactivateWindow(aura::Window* window);
@@ -52,6 +54,11 @@ ASH_EXPORT bool IsWindowUserPositionable(aura::Window* window);
 // Moves the window to the center of the display.
 ASH_EXPORT void CenterWindow(aura::Window* window);
 
+ASH_EXPORT gfx::Rect GetDefaultLeftSnappedWindowBoundsInParent(
+    wm::WmWindow* window);
+ASH_EXPORT gfx::Rect GetDefaultRightSnappedWindowBoundsInParent(
+    wm::WmWindow* window);
+
 // Returns the bounds of a left snapped window with default width in parent
 // coordinates.
 ASH_EXPORT gfx::Rect GetDefaultLeftSnappedWindowBoundsInParent(