[Media Router] Moves mojo-specific code into mojo/ folder

chrome/browser/media/router/test_helper.cc

Index: chrome/browser/media/router/test_helper.cc
diff --git a/chrome/browser/media/router/test_helper.cc b/chrome/browser/media/router/test_helper.cc
index 6bae9e184a49a6681aa78479b3ed69bbcf3ec697..edd5f49761e57b17d0ab5c27b714b0aad4bfabe9 100644
--- a/chrome/browser/media/router/test_helper.cc
+++ b/chrome/browser/media/router/test_helper.cc
@@ -24,11 +24,6 @@ MockMediaRoutesObserver::MockMediaRoutesObserver(MediaRouter* router,
 MockMediaRoutesObserver::~MockMediaRoutesObserver() {
 }
 
-MockEventPageTracker::MockEventPageTracker() {
-}
-MockEventPageTracker::~MockEventPageTracker() {
-}
-
 MockPresentationConnectionStateChangedCallback::
     MockPresentationConnectionStateChangedCallback() = default;