mus: Make --use-mus-in-renderer work again.

content/public/app/mojo/content_renderer_manifest.json

Index: content/public/app/mojo/content_renderer_manifest.json
diff --git a/content/public/app/mojo/content_renderer_manifest.json b/content/public/app/mojo/content_renderer_manifest.json
index faf008ebdd988251bc6f664fb6d1a170fe32c782..ecdacb2ca29f688e20b6592c47641d772ad2ce9e 100644
--- a/content/public/app/mojo/content_renderer_manifest.json
+++ b/content/public/app/mojo/content_renderer_manifest.json
@@ -3,6 +3,9 @@
   "name": "exe:content_renderer",
   "display_name": "Content Renderer",
   "capabilities": {
+    "provided": {
+      "app": [ "content::mojom::RenderWidgetWindowTreeClientFactory" ]

[Ben Goodger (Google), 2016/06/02 17:48:56]

I think you should explicitly require this interface in the content_browser
manifest, rather than introducing it into the app class, which I'm trying to
keep clean of content-isms

[sadrul, 2016/06/03 07:44:18]

Done.

+    },
     "required": {
       "mojo:mus": {
         "interfaces":  [ "mus::mojom::Gpu" ]