Revert of [NTP Snippets] Add unit tests for NTPSnippetsFetcher

components/ntp_snippets/ntp_snippets_fetcher.cc

Index: components/ntp_snippets/ntp_snippets_fetcher.cc
diff --git a/components/ntp_snippets/ntp_snippets_fetcher.cc b/components/ntp_snippets/ntp_snippets_fetcher.cc
index 7fe3d94b0e54b22c86e052357ff1bf1e2a1f0f48..2cb82135958e12b116cb883a50fef15634f8b8c3 100644
--- a/components/ntp_snippets/ntp_snippets_fetcher.cc
+++ b/components/ntp_snippets/ntp_snippets_fetcher.cc
@@ -86,6 +86,7 @@
 
 void NTPSnippetsFetcher::FetchSnippets(const std::set<std::string>& hosts,
                                        int count) {
+  // TODO(treib): What to do if there's already a pending request?
   const std::string& key = is_stable_channel_
                                ? google_apis::GetAPIKey()
                                : google_apis::GetNonStableAPIKey();