Enable DialMediaRouteProvider by default

Enable the feature flag for the native DIAL MediaRouteProvider by default.

Bug: 956621
Change-Id: Ied8686c0accfe46397b97890c9778f5876276484
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864013Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706970}

chrome/browser/media/router/media_router_feature.cc

@@ -32,7 +32,7 @@ namespace media_router {
 #if !defined(OS_ANDROID)
 // Controls if browser side DialMediaRouteProvider is enabled.
 const base::Feature kDialMediaRouteProvider{"DialMediaRouteProvider",
-                                            base::FEATURE_DISABLED_BY_DEFAULT};
+                                            base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Controls if browser side Cast device discovery is enabled.
 const base::Feature kEnableCastDiscovery{"EnableCastDiscovery",

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

@@ -67,11 +67,17 @@ class MediaRouterDesktopTestBase : public MediaRouterMojoTest {
   std::unique_ptr<MediaRouterMojoImpl> CreateMediaRouter() override {
     std::unique_ptr<MockCastMediaSinkService> cast_media_sink_service;
     if (enable_cast_discovery) {
-      feature_list_.InitWithFeatures({kEnableCastDiscovery}, {});
+      // We disable the DIAL MRP because initializing the DIAL MRP requires
+      // initialization of objects it depends on, which is outside the scope of
+      // this unit test. DIAL MRP initialization is covered by Media Router
+      // browser tests.
+      feature_list_.InitWithFeatures({kEnableCastDiscovery},
+                                     {kDialMediaRouteProvider});
       cast_media_sink_service = std::make_unique<MockCastMediaSinkService>();
       cast_media_sink_service_ = cast_media_sink_service.get();
     } else {
-      feature_list_.InitWithFeatures({}, {kEnableCastDiscovery});
+      feature_list_.InitWithFeatures(
+          {}, {kEnableCastDiscovery, kDialMediaRouteProvider});
     }
 
     media_sink_service_ = std::unique_ptr<DualMediaSinkService>(