Wrap MediaMetadata in base::Optional in content and chrome

content/browser/android/web_contents_observer_proxy.cc

Index: content/browser/android/web_contents_observer_proxy.cc
diff --git a/content/browser/android/web_contents_observer_proxy.cc b/content/browser/android/web_contents_observer_proxy.cc
index d0ed7b6815165407aa78c3ecb5ee9c25b97b91d7..6f01240f79448f2d1f7c80eb6fee4b4779023214 100644
--- a/content/browser/android/web_contents_observer_proxy.cc
+++ b/content/browser/android/web_contents_observer_proxy.cc
@@ -307,12 +307,14 @@ void WebContentsObserverProxy::DidStartNavigationToPendingEntry(
 void WebContentsObserverProxy::MediaSessionStateChanged(
     bool is_controllable,
     bool is_suspended,
-    const MediaMetadata& metadata) {
+    const base::Optional<MediaMetadata>& metadata) {
   JNIEnv* env = AttachCurrentThread();
 
   ScopedJavaLocalRef<jobject> obj(java_observer_);
-  ScopedJavaLocalRef<jobject> j_metadata =
-      MediaMetadataAndroid::CreateJavaObject(env, metadata);
+  ScopedJavaLocalRef<jobject> j_metadata;
+
+  if (metadata)
+    j_metadata = MediaMetadataAndroid::CreateJavaObject(env, metadata.value());
 
   Java_WebContentsObserverProxy_mediaSessionStateChanged(
       env, obj, is_controllable, is_suspended, j_metadata);