Refactor PhantomWindowController so that the PhantomWindowController owns the phantom window

ash/wm/workspace/workspace_window_resizer.h

Index: ash/wm/workspace/workspace_window_resizer.h
diff --git a/ash/wm/workspace/workspace_window_resizer.h b/ash/wm/workspace/workspace_window_resizer.h
index c0b654eb5843398b990c310aa6fb79e78686f081..47115b0c76266d6e3307f3b41219b9e4fbf95382 100644
--- a/ash/wm/workspace/workspace_window_resizer.h
+++ b/ash/wm/workspace/workspace_window_resizer.h
@@ -76,10 +76,6 @@ class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
  private:
   friend class WorkspaceWindowResizerTest;
 
-  // Returns the final bounds to place the window at. This differs from
-  // the current when snapping.
-  gfx::Rect GetFinalBounds(const gfx::Rect& bounds) const;
-
   // Lays out the attached windows. |bounds| is the bounds of the main window.
   void LayoutAttachedWindows(gfx::Rect* bounds);