Initial cut of ash/wm/common classes for mus

mash/wm/bridge/mus_layout_manager_adapter.h

+// 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 MASH_WM_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_
+#define MASH_WM_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "components/mus/public/cpp/window_observer.h"
+
+namespace ash {
+namespace wm {
+class WmLayoutManager;
+}
+}
+
+namespace mash {
+namespace wm {
+
+// Used to associate a mus::Window with an ash::wm::WmLayoutManager. This
+// attaches an observer to the mus::Window and calls the appropriate methods on
+// the WmLayoutManager at the appropriate time.
+//
+// NOTE: WmLayoutManager provides the function SetChildBounds(). This is
+// expected to be called to change the bounds of the Window. For aura this
+// function is called by way of aura exposing a hook (aura::LayoutManager). Mus
+// has no such hook. To ensure SetChildBounds() is called correctly all bounds
+// changes to mus::Windows must be routed through WmWindowMus. WmWindowMus
+// ensures WmLayoutManager::SetChildBounds() is called appropriately.
+class MusLayoutManagerAdapter : public mus::WindowObserver {
+ public:
+  MusLayoutManagerAdapter(
+      mus::Window* window,
+      std::unique_ptr<ash::wm::WmLayoutManager> layout_manager);
+  ~MusLayoutManagerAdapter() override;
+
+  ash::wm::WmLayoutManager* layout_manager() { return layout_manager_.get(); }
+
+ private:
+  // WindowObserver attached to child windows. A separate class is used to
+  // easily differentiate WindowObserver calls on the mus::Window associated
+  // with the MusLayoutManagerAdapter, vs children.
+  class ChildWindowObserver : public mus::WindowObserver {
+   public:
+    explicit ChildWindowObserver(MusLayoutManagerAdapter* adapter);
+    ~ChildWindowObserver() override;
+
+   private:
+    // mus::WindowObserver:
+    void OnWindowVisibilityChanged(mus::Window* window) override;
+
+    MusLayoutManagerAdapter* adapter_;
+
+    DISALLOW_COPY_AND_ASSIGN(ChildWindowObserver);
+  };
+
+  // mus::WindowObserver:
+  void OnTreeChanging(const TreeChangeParams& params) override;
+  void OnTreeChanged(const TreeChangeParams& params) override;
+  void OnWindowBoundsChanged(mus::Window* window,
+                             const gfx::Rect& old_bounds,
+                             const gfx::Rect& new_bounds) override;
+
+  mus::Window* window_;
+  ChildWindowObserver child_window_observer_;
+  std::unique_ptr<ash::wm::WmLayoutManager> layout_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(MusLayoutManagerAdapter);
+};
+
+}  // namespace wm
+}  // namespace mash
+
+#endif  // MASH_WM_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_