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

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

Index: chrome/browser/media/router/mojo/media_router_mojo_impl.cc
diff --git a/chrome/browser/media/router/mojo/media_router_mojo_impl.cc b/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
index d9c822cc294ccf15129f028caa447a5b06183d12..c2cacffcb0a6770c44880eb884c1b745bc236453 100644
--- a/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
+++ b/chrome/browser/media/router/mojo/media_router_mojo_impl.cc
@@ -20,6 +20,7 @@
 #include "chrome/browser/media/router/media_router_factory.h"
 #include "chrome/browser/media/router/media_routes_observer.h"
 #include "chrome/browser/media/router/media_sinks_observer.h"
+#include "chrome/browser/media/router/media_source_helper.h"
 #include "chrome/browser/media/router/mojo/media_route_provider_util_win.h"
 #include "chrome/browser/media/router/mojo/media_router_mojo_metrics.h"
 #include "chrome/browser/media/router/mojo/media_router_type_converters.h"
@@ -429,6 +430,10 @@ void MediaRouterMojoImpl::ClearIssue(const Issue::Id& issue_id) {
 }
 
 void MediaRouterMojoImpl::OnUserGesture() {
+  // Allow MRPM to intelligently update sinks and observers by passing in a
+  // media source.

[mark a. foltz, 2016/04/22 22:20:38]

I think some comment here about why we're discovering specifically for the
desktop source would be helpful.

+  UpdateMediaSinks(MediaSourceForDesktop().id());
+
 #if defined(OS_WIN)
   EnsureMdnsDiscoveryEnabled();
 #endif
@@ -988,4 +993,17 @@ void MediaRouterMojoImpl::OnFirewallCheckComplete(
 }
 #endif
 
+void MediaRouterMojoImpl::UpdateMediaSinks(
+    const MediaSource::Id& source_id) {
+  SetWakeReason(MediaRouteProviderWakeReason::UPDATE_MEDIA_SINKS);

[mark a. foltz, 2016/04/22 22:20:38]

We should see wakeups < the number of times the dialog is opened.

+  RunOrDefer(base::Bind(&MediaRouterMojoImpl::DoUpdateMediaSinks,
+                        base::Unretained(this), source_id));
+}
+
+void MediaRouterMojoImpl::DoUpdateMediaSinks(
+    const MediaSource::Id& source_id) {
+  DVLOG_WITH_INSTANCE(1) << "DoUpdateMediaSinks" << source_id;
+  media_route_provider_->UpdateMediaSinks(source_id);
+}
+
 }  // namespace media_router