Support additional mash shelf alignments.

mash/wm/window_manager_application.h

Index: mash/wm/window_manager_application.h
diff --git a/mash/wm/window_manager_application.h b/mash/wm/window_manager_application.h
index 46bbdc5bec75be20cc9f57451bcf414b01a86b9b..e9bb8a77942a81146ab00289f797da456e56d800 100644
--- a/mash/wm/window_manager_application.h
+++ b/mash/wm/window_manager_application.h
@@ -18,6 +18,7 @@
 #include "components/mus/public/interfaces/window_manager_factory.mojom.h"
 #include "components/mus/public/interfaces/window_tree_host.mojom.h"
 #include "mash/session/public/interfaces/session.mojom.h"
+#include "mash/wm/public/interfaces/shelf_layout.mojom.h"
 #include "mash/wm/public/interfaces/user_window_controller.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
@@ -49,6 +50,7 @@ class UserWindowControllerImpl;
 class WindowManagerApplication
     : public mojo::ShellClient,
       public mus::mojom::WindowManagerFactory,
+      public mojo::InterfaceFactory<mash::wm::mojom::ShelfLayout>,
       public mojo::InterfaceFactory<mash::wm::mojom::UserWindowController>,
       public mojo::InterfaceFactory<mus::mojom::AcceleratorRegistrar> {
  public:
@@ -91,6 +93,11 @@ class WindowManagerApplication
                   uint32_t id) override;
   bool AcceptConnection(mojo::Connection* connection) override;
 
+  // InterfaceFactory<mash::wm::mojom::ShelfLayout>:
+  void Create(
+      mojo::Connection* connection,
+      mojo::InterfaceRequest<mash::wm::mojom::ShelfLayout> request) override;
+
   // InterfaceFactory<mash::wm::mojom::UserWindowController>:
   void Create(mojo::Connection* connection,
               mojo::InterfaceRequest<mash::wm::mojom::UserWindowController>
@@ -113,11 +120,18 @@ class WindowManagerApplication
   std::unique_ptr<ui::mojo::UIInit> ui_init_;
   std::unique_ptr<views::AuraInit> aura_init_;
 
+  // The ShelfLayout object is created once OnEmbed() is called. Until that

[msw, 2016/04/12 00:33:17]

Also, it's unclear that we actually encounter this situation; can we just drop
any requests for Shelf or UserWindowController before they exist?

[sky, 2016/04/13 23:44:11]

What guarantees that? By that I mean how do you know that ShelfLayout and/or
UnserWindowController is not asked for before OnEmbed?

[msw, 2016/04/15 17:25:06]

I guess nothing guarantees that, it just seems odd to support shelf interaction
before the window manager is initialized, and that doesn't happen in my testing.

[sky, 2016/04/15 19:33:23]

It shouldn't be hard to get this scenario in a test. Connect to the desktop_wm
directly and ask for the shelflayout. If mus isn't running that request will be
seen before OnEmbed.

+  // time |shelf_layout_requests_| stores pending interface requests.
+  mojo::BindingSet<mash::wm::mojom::ShelfLayout> shelf_layout_bindings_;
+  std::vector<
+      std::unique_ptr<mojo::InterfaceRequest<mash::wm::mojom::ShelfLayout>>>
+      shelf_layout_requests_;
+
   // |user_window_controller_| is created once OnEmbed() is called. Until that
   // time |user_window_controller_requests_| stores pending interface requests.
   std::unique_ptr<UserWindowControllerImpl> user_window_controller_;
   mojo::BindingSet<mash::wm::mojom::UserWindowController>
-      user_window_controller_binding_;
+      user_window_controller_bindings_;
   std::vector<std::unique_ptr<
       mojo::InterfaceRequest<mash::wm::mojom::UserWindowController>>>
       user_window_controller_requests_;