[NTP Snippets] Don't attempt to fetch remote suggestions without API key

components/ntp_snippets/remote/json_request.h

 // Copyright 2016 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_REMOTE_JSON_REQUEST_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_JSON_REQUEST_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 26 matching lines @@
 enum class FetchResult {
   SUCCESS = 0,
   // DEPRECATED_EMPTY_HOSTS = 1,
   URL_REQUEST_STATUS_ERROR = 2,
   HTTP_ERROR = 3,
   JSON_PARSE_ERROR = 4,
   INVALID_SNIPPET_CONTENT_ERROR = 5,
   OAUTH_TOKEN_ERROR = 6,
   // DEPRECATED_INTERACTIVE_QUOTA_ERROR = 7,
   // DEPRECATED_NON_INTERACTIVE_QUOTA_ERROR = 8,
-  RESULT_MAX = 9
+  MISSING_API_KEY = 9,
+  RESULT_MAX = 10
 };
 
 enum FetchAPI {
   CHROME_READER_API,
   CHROME_CONTENT_SUGGESTIONS_API,
 };
 
 // A single request to query remote suggestions. On success, the suggestions are
 // returned in parsed JSON form (base::Value).
 class JsonRequest : public net::URLFetcherDelegate {
@@ skipping 119 matching lines @@
   base::WeakPtrFactory<JsonRequest> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(JsonRequest);
 };
 
 }  // namespace internal
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_JSON_REQUEST_H_