Fix broken clockstate.network2 histogram and add unit test

components/network_time/network_time_tracker.h

Index: components/network_time/network_time_tracker.h
diff --git a/components/network_time/network_time_tracker.h b/components/network_time/network_time_tracker.h
index 5e31411d16257b3e1b4b34cc30c5f5d9852f5336..72f342198d314a46e124aa4f03769bea46451d77 100644
--- a/components/network_time/network_time_tracker.h
+++ b/components/network_time/network_time_tracker.h
@@ -127,6 +127,8 @@ class NetworkTimeTracker : public net::URLFetcherDelegate {
 
   base::TimeDelta GetTimerDelayForTesting() const;
 
+  void EnableTimeQueriesForTesting();
+
  private:
   // Checks whether a network time query should be issued, and issues one if so.
   // Upon response, execution resumes in |OnURLFetchComplete|.
@@ -161,6 +163,8 @@ class NetworkTimeTracker : public net::URLFetcherDelegate {
   base::TimeTicks fetch_started_;
   std::unique_ptr<client_update_protocol::Ecdsa> query_signer_;
 
+  bool enable_time_queries_for_testing_ = false;
+
   // Run by WaitForFetchForTesting() and quit by OnURLFetchComplete().
   base::RunLoop* run_loop_for_testing_ = nullptr;