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

components/ntp_snippets/ntp_snippets_service.h

Index: components/ntp_snippets/ntp_snippets_service.h
diff --git a/components/ntp_snippets/ntp_snippets_service.h b/components/ntp_snippets/ntp_snippets_service.h
index ea0aabab27cd05e6f1edf4e07f41382d869b9351..07ad7a42e5afe52aaddd99730bfdfcac3a9d9991 100644
--- a/components/ntp_snippets/ntp_snippets_service.h
+++ b/components/ntp_snippets/ntp_snippets_service.h
@@ -178,9 +178,9 @@ class NTPSnippetsService : public KeyedService {
 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() {}