mash: Port ash_sysui ShelfDelegateMus impl to mojo:ash.

ash/public/interfaces/shelf.mojom

Index: ash/public/interfaces/shelf.mojom
diff --git a/mash/shelf/public/interfaces/shelf.mojom b/ash/public/interfaces/shelf.mojom
similarity index 77%
rename from mash/shelf/public/interfaces/shelf.mojom
rename to ash/public/interfaces/shelf.mojom
index 077900260d27d46894f22f8b0deb5fa0e971e719..285af1ef5419cec23368b4ac9d8e210862235bda 100644
--- a/mash/shelf/public/interfaces/shelf.mojom
+++ b/ash/public/interfaces/shelf.mojom
@@ -2,19 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module mash.shelf.mojom;
+module ash.mojom;
 
-import "mash/shelf/public/interfaces/shelf_constants.mojom";
 import "skia/public/interfaces/bitmap.mojom";
 
-// TODO(msw): Add support for multiple displays (with unified and multi-shelf).
+// These values match ash::ShelfAlignment.
+enum ShelfAlignment { BOTTOM, LEFT, RIGHT, BOTTOM_LOCKED, };
 
-// The Shelf controller allows clients (eg. Chrome) to control the mash shelf.
+// These values match ash::ShelfAutoHideBehavior.
+enum ShelfAutoHideBehavior { ALWAYS, NEVER, HIDDEN, };
+
+// The Shelf controller allows clients (eg. Chrome) to control the ash shelf.
 interface ShelfController {
   AddObserver(associated ShelfObserver observer);

[James Cook, 2016/08/19 22:43:31]

Does the observer get notified with the current state when it is added? Might
want to document that.

(I'm a stickler for docs in mojom/IDL files.)

[msw, 2016/08/19 23:05:54]

Done.

 
-  SetAlignment(Alignment alignment);
-  SetAutoHideBehavior(AutoHideBehavior auto_hide);
+  SetAlignment(ShelfAlignment alignment, int64 display_id);

[James Cook, 2016/08/19 22:43:31]

Q: Where does Chrome set the alignment/auto-hide behavior? When it loads the
setting from profile storage?

Also, these methods could use some short docs, maybe referring to WmShelf for
details.

[msw, 2016/08/19 23:05:54]

Yeah, ChromeMashShelfController sets the alignment and auto-hide from prefs on
init (chrome startup), and in OnShelfCreated (when displays are connected).

+  SetAutoHideBehavior(ShelfAutoHideBehavior auto_hide, int64 display_id);
 
   PinItem(ShelfItem item, associated ShelfItemDelegate delegate);
   UnpinItem(string app_id);
@@ -24,8 +27,9 @@ interface ShelfController {
 
 // ShelfObserver is notified on shelf changes; used to persist profile settings.
 interface ShelfObserver {
-  OnAlignmentChanged(Alignment alignment);
-  OnAutoHideBehaviorChanged(AutoHideBehavior auto_hide);
+  OnShelfCreated(int64 display_id);
+  OnAlignmentChanged(ShelfAlignment alignment, int64 display_id);
+  OnAutoHideBehaviorChanged(ShelfAutoHideBehavior auto_hide, int64 display_id);
 };
 
 // ShelfItemDelegate handles command execution and observes shelf item changes.