mash: Port ash_sysui ShelfDelegateMus impl to mojo:ash.

ash/mus/DEPS

Index: ash/mus/DEPS
diff --git a/ash/mus/DEPS b/ash/mus/DEPS
index 39227f60b61cb0c53f0543139d0854ff627e760c..e17f0005e73cb99a153e86b4dc4df9d3fe3739bf 100644
--- a/ash/mus/DEPS
+++ b/ash/mus/DEPS
@@ -14,3 +14,14 @@ include_rules = [
   "+services/shell/public",
   "+services/tracing/public",
 ]
+# Shelf code is being moved into //ash/common. Please ask jamescook@ or msw@
+# before adding items here. http://crbug.com/615155
+specific_include_rules = {
+  "root_window_controller.cc": [
+    "+ash/shelf/shelf_layout_manager.h",
+  ],
+  "shelf_delegate_mus.cc": [
+    "+ash/shelf/shelf.h",
+    "+ash/shelf/shelf_widget.h",
+  ],
+}