Use mojo SystemTray interfaces for both mash and classic ash

chrome/app/mojo/chrome_manifest.json

Index: chrome/app/mojo/chrome_manifest.json
diff --git a/chrome/app/mojo/chrome_manifest.json b/chrome/app/mojo/chrome_manifest.json
index 3abfa8540aa0e1dd74c36989c84c4b754f307b0c..b6f405f21759a9a0f97eb1293bb643b30f008302 100644
--- a/chrome/app/mojo/chrome_manifest.json
+++ b/chrome/app/mojo/chrome_manifest.json
@@ -16,6 +16,13 @@
          "interfaces": [ "ash::autoclick::mojom::AutoclickController" ]
       }
     },
-    "provided": { "mash:launchable": [ "mash::mojom::Launchable" ] }
+    "provided": {
+      "mash:launchable": [
+        "mash::mojom::Launchable"
+      ],
+      "ash": [

[msw, 2016/09/30 23:26:49]

It might be nice to avoid using classes; but maybe that's just my preference (I
prefer that clients call out the explicit interfaces needed, rather than an
alias to a set of interfaces)

[James Cook, 2016/10/03 18:07:56]

Me too, but rockot recommended I do it this way. (Don't you have to put provided
interfaces in classes?) rockot, thoughts?

[msw, 2016/10/03 19:04:43]

No, you don't *need* to put provided interfaces in classes, afaik. It'd be good
to get one more look here from rockot@, but it's not a big deal.

[James Cook, 2016/10/03 20:15:00]

rockot, thoughts?

+        "ash::mojom::SystemTrayClient"
+      ]
+    }
   }
 }