Allow dumping raw json fetched from the server.

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 e0eafaf90bce3e7c2efb7c190e47bc4af953630b..e958ade8a27054118944400d0880593c90a41844 100644
--- a/components/ntp_snippets/ntp_snippets_service.h
+++ b/components/ntp_snippets/ntp_snippets_service.h
@@ -85,6 +85,11 @@ class NTPSnippetsService : public KeyedService {
     return last_fetch_status_;
   }
 
+  // Returns the last json from the snippets fetcher.
+  const std::string& last_json() const {
+    return last_fetch_json_;
+  }
+
   // (Re)schedules the periodic fetching of snippets. This is necessary because
   // the schedule depends on the time of day
   void RescheduleFetching();
@@ -202,6 +207,8 @@ class NTPSnippetsService : public KeyedService {
 
   std::string last_fetch_status_;
 
+  std::string last_fetch_json_;
+
   // Timer that calls us back when the next snippet expires.
   base::OneShotTimer expiry_timer_;