[MediaRouter] Add implementation of PresentationServiceDelegate

chrome/browser/media/router/media_source_helper_unittest.cc

Index: chrome/browser/media/router/media_source_helper_unittest.cc
diff --git a/chrome/browser/media/router/media_source_helper_unittest.cc b/chrome/browser/media/router/media_source_helper_unittest.cc
index fe360465328fb133e007ced460e979d9f29dce0f..58437d36d22032c9335a1f17c075ae982f90a8c2 100644
--- a/chrome/browser/media/router/media_source_helper_unittest.cc
+++ b/chrome/browser/media/router/media_source_helper_unittest.cc
@@ -40,5 +40,12 @@ TEST(MediaSourcesTest, IsValidMediaSource) {
   EXPECT_FALSE(IsValidMediaSource(ForPresentationUrl("totally not a url")));
 }
 
+TEST(MediaSourcesTest, GetPresentationUrl) {
+  EXPECT_EQ("", GetPresentationUrl(ForTabMediaSource(123)));
+  EXPECT_EQ("", GetPresentationUrl(ForDesktopMediaSource()));
+  EXPECT_EQ("http://example.com/",
+            GetPresentationUrl(ForPresentationUrl("http://example.com/")));
+}
+
 }  // namespace media_router