Creates mus implementation of WmShelf

mash/wm/bridge/wm_shelf_mus.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_WM_SHELF_MUS_H_
+#define MASH_WM_BRIDGE_WM_SHELF_MUS_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "ash/wm/common/shelf/wm_shelf.h"
+#include "base/macros.h"
+#include "base/observer_list.h"
+
+namespace mash {
+namespace wm {
+
+class ShelfLayoutManager;
+
+// WmShelf implementation for mus.
+class WmShelfMus : public ash::wm::WmShelf {
+ public:
+  explicit WmShelfMus(ShelfLayoutManager* shelf_layout_manager);
+  ~WmShelfMus() override;
+
+  // ash::wm::WmShelf:

[msw, 2016/05/18 00:37:30]

Hmm, I'm trying to understand why this is needed in addition to
ash/shelf/shelf.h... Shouldn't that Shelf class itself support either window
type for use by the ash or mash wm? (isn't the mash wm part of ash_sysui? if
not, wouldn't this need to be a mojo interface like ShelfController?) Sorry, I'm
not up to speed here.

[sky, 2016/05/18 16:18:32]

The mash wm (aka desktop_wm) is not part of ash_sysui.

As part of window management mash wm needs to know and communicate with the
shelf. For example, the mash wm may need to hide the shelf in certain
situations, and it needs to know shelf alignment for positioning other windows.
ash::wm::WmShelf is the shelf api needed by both the window management code in
ash and mash. This class, WmShelfMus, is that implementation for mash.

ash contains at least two sets of functionality:
. window management.
. creating various shell widgets.

The mash wm wants the window management from ash, but not the rest of it.
Additionally the window management code in mash should be in terms of
mus::Window, not aura::Window. I refactored the window management code in ash so
that it is not in terms of aura::Window and is self contained. By self contained
I mean the code does not depend upon the rest of ash or aura::Window. This code
lives in ash/wm/common. The window management code defines a handful of pure
virtual classes. The implementation for ash in terms of aura lives in
ash/wm/aura. The implementation of these classes for mash lives in
mash/wm/bridge. If you think of the dependencies of ash and mash_wm,
ash/wm/common is a piece that both depend upon with very minimal dependencies it
self (
https://chromium.googlesource.com/chromium/src/+/master/ash/wm/common/DEPS ).

So, WmShelfMus is the implementation of the shelf api needed by the common
window management code for mash. As to should this be a mojom. The porting
layer, WmShelf, shouldn't be a mojom, but as you say, this class will need to
communicate via a mojom.

When mash is shipping we can nuke the porting classes (such as
WmShelf/WmShelfMus/WmShelfAura) and have the common window management code talk
directly to mus/mash types.

Make sense?

[msw, 2016/05/18 17:25:35]

That does make sense, thanks for the thoughtful explanation.

+  ash::wm::WmWindow* GetWindow() override;
+  ash::wm::ShelfAlignment GetAlignment() const override;
+  ash::wm::ShelfBackgroundType GetBackgroundType() const override;
+  void UpdateVisibilityState() override;
+  ash::ShelfVisibilityState GetVisibilityState() const override;
+  void UpdateIconPositionForWindow(ash::wm::WmWindow* window) override;
+  gfx::Rect GetScreenBoundsOfItemIconForWindow(
+      ash::wm::WmWindow* window) override;
+  void AddObserver(ash::wm::WmShelfObserver* observer) override;
+  void RemoveObserver(ash::wm::WmShelfObserver* observer) override;
+
+  base::ObserverList<ash::wm::WmShelfObserver> observers_;

[msw, 2016/05/18 00:37:30]

Make these private (here or above).

[sky, 2016/05/18 16:18:32]

Done.

+
+  ShelfLayoutManager* shelf_layout_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(WmShelfMus);
+};
+
+}  // namespace wm
+}  // namespace mash
+
+#endif  // MASH_WM_BRIDGE_WM_SHELF_MUS_H_