[Media Router] Add logs in DIAL MRP

Bug: b/170651374, 1117673
Change-Id: Iba8a5c71033514e560bb5b3d1b5274379cbe5245
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2464788Reviewed-by: Takumi Fujimoto <takumif@chromium.org>
Commit-Queue: Muyao Xu <muyaoxu@google.com>
Cr-Commit-Position: refs/heads/master@{#817279}

chrome/browser/media/router/providers/dial/dial_media_route_provider.h

@@ -200,6 +200,9 @@ class DialMediaRouteProvider : public mojom::MediaRouteProvider,
 
   DialInternalMessageUtil internal_message_util_;
 
+  // Mojo remote to the logger owned by the Media Router.
+  mojo::Remote<mojom::Logger> logger_;
+
   SEQUENCE_CHECKER(sequence_checker_);
   base::WeakPtrFactory<DialMediaRouteProvider> weak_ptr_factory_{this};
   DISALLOW_COPY_AND_ASSIGN(DialMediaRouteProvider);