Introduce window container to be used by lock screen app windows

ash/screen_util.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_SCREEN_UTIL_H_
 #define ASH_SCREEN_UTIL_H_
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
 
@@ skipping 12 matching lines @@
   // Returns the bounds for maximized windows in parent coordinates.
   // Maximized windows trigger auto-hiding the shelf.
   static gfx::Rect GetMaximizedWindowBoundsInParent(aura::Window* window);
 
   // Returns the display bounds in parent coordinates.
   static gfx::Rect GetDisplayBoundsInParent(aura::Window* window);
 
   // Returns the display's work area bounds in parent coordinates.
   static gfx::Rect GetDisplayWorkAreaBoundsInParent(aura::Window* window);
 
+  // Returns the display's work area bounds in parent coordinates on lock
+  // screen, i.e. for work area with forced bottom alignment.
+  // Note that unlike |GetDisplayWorkAreaBoundsInParent|, this method uses
+  // work area bounds that are updated when the screen is locked. For example
+  // if shelf alignment is set to right before screen lock,
+  // |GetDisplayWorkAreaBoundsInParent| will return work are bounds for right
+  // shelf alignment - this method will return work area for bottom shelf
+  // alignment (which is always used on lock screen).
+  static gfx::Rect GetDisplayWorkAreaBoundsInParentForLockScreen(
+      aura::Window* window);
+
   // Returns the bounds of the physical display containing the shelf for
   // |window|. Physical displays can differ from logical displays in unified
   // desktop mode.
   // TODO(oshima): Consider using physical displays in window layout, instead of
   // root windows, and only use logical display in display management code.
   static gfx::Rect GetDisplayBoundsWithShelf(aura::Window* window);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ScreenUtil);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SCREEN_UTIL_H_