Converts DockedWindowLayoutManager to common ash/wm types

ash/wm/common/wm_snap_to_pixel_layout_manager.h

Index: ash/wm/common/wm_snap_to_pixel_layout_manager.h
diff --git a/ash/wm/common/wm_snap_to_pixel_layout_manager.h b/ash/wm/common/wm_snap_to_pixel_layout_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..b5f865811b79a9889b258d614539519b3d5331fa
--- /dev/null
+++ b/ash/wm/common/wm_snap_to_pixel_layout_manager.h
@@ -0,0 +1,39 @@
+// Copyright 2016 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_WM_COMMON_WM_SNAP_TO_PIXEL_LAYOUT_MANAGER_H_
+#define ASH_WM_COMMON_WM_SNAP_TO_PIXEL_LAYOUT_MANAGER_H_
+
+#include "ash/ash_export.h"
+#include "ash/wm/common/wm_layout_manager.h"
+#include "base/macros.h"
+
+namespace ash {
+namespace wm {
+
+// A layout manager that places children's layer at the physical pixel
+// boundaries.
+class ASH_EXPORT WmSnapToPixelLayoutManager : public WmLayoutManager {
+ public:
+  WmSnapToPixelLayoutManager();
+  ~WmSnapToPixelLayoutManager() override;
+
+ protected:
+  // Overridden from aura::LayoutManager:
+  void OnWindowResized() override;
+  void OnWindowAddedToLayout(WmWindow* child) override;
+  void OnWillRemoveWindowFromLayout(WmWindow* child) override;
+  void OnWindowRemovedFromLayout(WmWindow* child) override;
+  void OnChildWindowVisibilityChanged(WmWindow* child, bool visibile) override;
+  void SetChildBounds(WmWindow* child,
+                      const gfx::Rect& requested_bounds) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WmSnapToPixelLayoutManager);
+};
+
+}  // namespace wm
+}  // namespace ash
+
+#endif  // ASH_WM_COMMON_WM_SNAP_TO_PIXEL_LAYOUT_MANAGER_H_