Android: Remove unneeded RegisterNatives() calls

chrome/browser/push_messaging/push_messaging_service_observer_android.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 CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_SERVICE_OBSERVER_ANDROID_H_
 #define CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_SERVICE_OBSERVER_ANDROID_H_
 
 #include "chrome/browser/push_messaging/push_messaging_service_observer.h"
 
 #include <jni.h>
 
 #include "base/macros.h"
 
 // Observer for the PushMessagingService to be used on Android for forwarding
 // message handled events to listeners in Java.
 class PushMessagingServiceObserverAndroid
     : public PushMessagingServiceObserver {
  public:
-  static bool RegisterJni(JNIEnv* env);
-
   // PushMessagingServiceObserver implementation.
   void OnMessageHandled() override;
 
  private:
   friend class PushMessagingServiceObserver;
   PushMessagingServiceObserverAndroid() {}
 
   DISALLOW_COPY_AND_ASSIGN(PushMessagingServiceObserverAndroid);
 };
 
 #endif  // CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_SERVICE_OBSERVER_ANDROID_H_