[Media>UI] Reset media metadata when navigating away

chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java
index fec8d6e6904204454ebc60e8d49adfa62b722773..1e5c33367dccd9770965dc9e323028f85178d66c 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaSessionTabHelper.java
@@ -284,9 +284,12 @@ public class MediaSessionTabHelper implements MediaImageCallback {
         }
 
         @Override
-        public void onUrlUpdated(Tab tab) {
+        public void onDidNavigateMainFrame(Tab tab, String url, String baseUrl,
+                boolean isNavigationToDifferentPage, boolean isFragmentNavigation, int statusCode) {
             assert tab == mTab;
 
+            if (!isNavigationToDifferentPage) return;
+
             String origin = mTab.getUrl();
             try {
                 origin = UrlFormatter.formatUrlForSecurityDisplay(new URI(origin), true);
@@ -299,12 +302,20 @@ public class MediaSessionTabHelper implements MediaImageCallback {
             mOrigin = origin;
             mFavicon = null;
             mPageMediaImage = null;
+            mPageMetadata = null;
+            // |mCurrentMetadata| selects either |mPageMetadata| or |mFallbackTitle|. As there is no
+            // guarantee {@link #onTitleUpdated()} will be called before or after this method,
+            // |mFallbackTitle| is not reset in this callback, i.e. relying solely on
+            // {@link #onTitleUpdated()}. The following assignment is to keep |mCurrentMetadata| up
+            // to date as |mPageMetadata| may have changed.
+            mCurrentMetadata = getMetadata();
 
             if (isNotificationHiddingOrHidden()) return;
 
             mNotificationInfoBuilder.setOrigin(mOrigin);
             mNotificationInfoBuilder.setNotificationLargeIcon(mFavicon);
             mNotificationInfoBuilder.setMediaSessionImage(mPageMediaImage);
+            mNotificationInfoBuilder.setMetadata(mCurrentMetadata);
             showNotification();
         }