[Media Router] Wire through a new MRPM call to update media sinks.

chrome/browser/media/router/mojo/media_router_mojo_impl.h

Index: chrome/browser/media/router/mojo/media_router_mojo_impl.h
diff --git a/chrome/browser/media/router/mojo/media_router_mojo_impl.h b/chrome/browser/media/router/mojo/media_router_mojo_impl.h
index 0106bd506789b78f6c8da905577a2b25636cfeaa..dd07bed7c3bfe7d50f221b2e55a9cccce058123d 100644
--- a/chrome/browser/media/router/mojo/media_router_mojo_impl.h
+++ b/chrome/browser/media/router/mojo/media_router_mojo_impl.h
@@ -335,6 +335,11 @@ class MediaRouterMojoImpl : public MediaRouterBase,
   void OnFirewallCheckComplete(bool firewall_can_use_local_ports);
 #endif
 
+  // Signal MRPM to initiate discovery.  This allows MRPs that only do discovery
+  // on sink queries to return results even if the MRP sink state is marked
+  // UNAVAILABLE.
+  void DoUserGestureDiscovery();
+
   // Pending requests queued to be executed once component extension
   // becomes ready.
   std::deque<base::Closure> pending_requests_;