ash/mash: Introduce a ShelfDelegate implementation for mash.

ash/mus/sysui/sysui_application.cc

Index: ash/mus/sysui/sysui_application.cc
diff --git a/ash/mus/sysui/sysui_application.cc b/ash/mus/sysui/sysui_application.cc
index 12693068bbdfa8db3b166e921f2542a2dcf37e78..adaabf48932952c35dd893118ef242606648b641 100644
--- a/ash/mus/sysui/sysui_application.cc
+++ b/ash/mus/sysui/sysui_application.cc
@@ -99,10 +99,15 @@ class NativeWidgetFactory {
                 static_cast<int32_t>(container));
       }
     }
+
+    ui::ContextFactory* factory = aura::Env::GetInstance()->context_factory();

[msw, 2016/02/09 18:31:26]

This seems like a tangential workaround; care to add a comment?

[sadrul, 2016/02/10 08:04:41]

Split into a separate CL: https://codereview.chromium.org/1679023007

+    aura::Env::GetInstance()->set_context_factory(nullptr);
     views::NativeWidgetMus* native_widget =
         static_cast<views::NativeWidgetMus*>(
             views::WindowManagerConnection::Get()->CreateNativeWidgetMus(
                 properties, params, delegate));
+    aura::Env::GetInstance()->set_context_factory(factory);
+
     // TODO: Set the correct display id here.
     InitRootWindowSettings(native_widget->GetRootWindow())->display_id =
         Shell::GetInstance()