Implement MediaMetadata artwork in content

content/browser/android/web_contents_observer_proxy.h

 // 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.
 
 #ifndef CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_PROXY_H_
 #define CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_PROXY_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
@@ skipping 55 matching lines @@
   void NavigationEntryCommitted(
       const LoadCommittedDetails& load_details) override;
   void WebContentsDestroyed() override;
   void DidAttachInterstitialPage() override;
   void DidDetachInterstitialPage() override;
   void DidChangeThemeColor(SkColor color) override;
   void DidStartNavigationToPendingEntry(
       const GURL& url,
       NavigationController::ReloadType reload_type) override;
   void MediaSessionStateChanged(bool is_controllable,
-                                bool is_suspended,
-                                const MediaMetadata& metadata) override;
+                                bool is_suspended) override;
+  void MediaMetadataChanged(const MediaMetadata& metadata) override;
+
   void SetToBaseURLForDataURLIfNeeded(std::string* url);
 
   void DidFailLoadInternal(bool is_provisional_load,
                            bool is_main_frame,
                            int error_code,
                            const base::string16& description,
                            const GURL& url,
                            bool was_ignored_by_handler);
 
   base::android::ScopedJavaGlobalRef<jobject> java_observer_;
   GURL base_url_of_last_started_data_url_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserverProxy);
 };
 
 bool RegisterWebContentsObserverProxy(JNIEnv* env);
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_PROXY_H_