Implement MediaMetadata artwork in content

content/browser/android/web_contents_observer_proxy.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/android/web_contents_observer_proxy.h"
 
 #include <string>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
@@ skipping 297 matching lines @@
       env, obj.obj(), jstring_url.obj());
 }
 
 void WebContentsObserverProxy::MediaSessionStateChanged(
     bool is_controllable,
     bool is_suspended,
     const MediaMetadata& metadata) {
   JNIEnv* env = AttachCurrentThread();
 
   ScopedJavaLocalRef<jobject> obj(java_observer_);
+
+  // TODO(zqzhang): the metadata is sent though JNI everytime the media session
+  // play/pause state changes. Need to find a way to seprate the state change
+  // and Metadata update. See https://crbug.com/621855.
   ScopedJavaLocalRef<jobject> j_metadata =
       MediaMetadataAndroid::CreateJavaObject(env, metadata);
 
   Java_WebContentsObserverProxy_mediaSessionStateChanged(
       env, obj.obj(), is_controllable, is_suspended, j_metadata.obj());
 }
 
 void WebContentsObserverProxy::SetToBaseURLForDataURLIfNeeded(
     std::string* url) {
   NavigationEntry* entry =
       web_contents()->GetController().GetLastCommittedEntry();
   // Note that GetBaseURLForDataURL is only used by the Android WebView.
   // FIXME: Should we only return valid specs and "about:blank" for invalid
   // ones? This may break apps.
   if (entry && !entry->GetBaseURLForDataURL().is_empty()) {
     *url = entry->GetBaseURLForDataURL().possibly_invalid_spec();
   } else if (!base_url_of_last_started_data_url_.is_empty()) {
     // NavigationController can lose the pending entry and recreate it without
     // a base URL if there has been a loadUrl("javascript:...") after
     // loadDataWithBaseUrl.
     *url = base_url_of_last_started_data_url_.possibly_invalid_spec();
   }
 }
 
 bool RegisterWebContentsObserverProxy(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 }  // namespace content