Adds WmLayoutManager and the aura wrapper AuraLayoutManagerAdapter

ash/wm/common/wm_layout_manager.h

Index: ash/wm/common/wm_layout_manager.h
diff --git a/ash/wm/common/wm_layout_manager.h b/ash/wm/common/wm_layout_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..d8be091f5a964fe3ddade21eca95c1b301d45f41
--- /dev/null
+++ b/ash/wm/common/wm_layout_manager.h
@@ -0,0 +1,57 @@
+// 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_LAYOUT_MANAGER_H_
+#define ASH_WM_COMMON_WM_LAYOUT_MANAGER_H_
+
+#include "ash/ash_export.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace ash {
+namespace wm {
+
+class WmWindow;
+
+// Used to position the child WmWindows of a WmWindow. WmLayoutManager is called
+// at key points in a WmWindows life cycle thats allow sthe WmLayoutManager to
+// position or change child WmWindows.
+class ASH_EXPORT WmLayoutManager {
+ public:
+  virtual ~WmLayoutManager() {}
+
+  // Invoked when the window the WmLayoutManager is associated with is resized.
+  virtual void OnWindowResized() = 0;
+
+  // Invoked when a window is added to the window the WmLayoutManager is
+  // associated with.
+  virtual void OnWindowAddedToLayout(WmWindow* child) = 0;
+
+  // Invoked prior to removing |child|.
+  virtual void OnWillRemoveWindowFromLayout(WmWindow* child) = 0;
+
+  // Invoked after removing |child|.
+  virtual void OnWindowRemovedFromLayout(WmWindow* child) = 0;
+
+  // Invoked when SetVisible() is invoked on |child|. |visible| is the value
+  // supplied to SetVisible(). If |visible| is true, child->IsVisible() may
+  // still return false. See description in aura::Window::IsVisible() for
+  // details.
+  virtual void OnChildWindowVisibilityChanged(WmWindow* child,
+                                              bool visibile) = 0;
+
+  // Invoked when WmWindow::SetBounds() is called on |child|. This allows the
+  // WmLayoutManager to modify the bounds as appropriate before processing the
+  // request, including ignoring the request. Implementation must call
+  // SetChildBoundsDirect() so that an infinite loop does not result.
+  virtual void SetChildBounds(WmWindow* child,
+                              const gfx::Rect& requested_bounds) = 0;
+};
+
+}  // namespace wm
+}  // namespace ash
+
+#endif  // ASH_WM_COMMON_WM_LAYOUT_MANAGER_H_