[NTP Snippets] SnippetsBridge: register as SnippetsObserver only when we get a Java observer

components/ntp_snippets/ntp_snippets_service.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 COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 160 matching lines @@
   const ParseJSONCallback parse_json_callback_;
 
   base::WeakPtrFactory<NTPSnippetsService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsService);
 };
 
 class NTPSnippetsServiceObserver {
  public:
   // Sent every time the service loads a new set of data.
-  virtual void NTPSnippetsServiceLoaded(NTPSnippetsService* service) = 0;
+  virtual void NTPSnippetsServiceLoaded() = 0;
   // Sent when the service is shutting down.
-  virtual void NTPSnippetsServiceShutdown(NTPSnippetsService* service) = 0;
+  virtual void NTPSnippetsServiceShutdown() = 0;
 
  protected:
   virtual ~NTPSnippetsServiceObserver() {}
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_