Remove one thread hop while fetching matching rules

chrome/browser/android/data_usage/external_data_use_observer_unittest.cc

Index: chrome/browser/android/data_usage/external_data_use_observer_unittest.cc
diff --git a/chrome/browser/android/data_usage/external_data_use_observer_unittest.cc b/chrome/browser/android/data_usage/external_data_use_observer_unittest.cc
index dbe89efb10f73d90dffb3ac17553c1ed7f7ddbc2..b5137ccc8d2a4d3bf5a4b3d7458d48127a0e5cfc 100644
--- a/chrome/browser/android/data_usage/external_data_use_observer_unittest.cc
+++ b/chrome/browser/android/data_usage/external_data_use_observer_unittest.cc
@@ -399,10 +399,17 @@ TEST_F(ExternalDataUseObserverTest, MatchingRuleFetchOnControlAppInstall) {
   EXPECT_TRUE(
       external_data_use_observer()->last_matching_rules_fetch_time_.is_null());
 
-  // Matching rules fetched on every navigation if control app is installed and
-  // zero rules are available.
+  // Matching rules are fetched when control app gets installed.
   external_data_use_observer()
       ->data_use_tab_model_->OnControlAppInstallStateChange(true);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(
+      external_data_use_observer()->last_matching_rules_fetch_time_.is_null());
+
+  // Matching rules fetched on every navigation if control app is installed and
+  // zero rules are available.
+  external_data_use_observer()->last_matching_rules_fetch_time_ =
+      base::TimeTicks();
   external_data_use_observer()->data_use_tab_model_->OnNavigationEvent(
       kDefaultTabId, DataUseTabModel::TRANSITION_LINK, GURL(kDefaultURL),
       std::string());
@@ -586,13 +593,15 @@ TEST_F(ExternalDataUseObserverTest, DataUseReportTimedOut) {
 
   // Create another ExternalDataUseObserver object.
   ReplaceExternalDataUseObserver(variation_params);
+  histogram_tester.ExpectTotalCount(kUMAMatchingRuleFirstFetchDurationHistogram,
+                                    0);
 
-  // Trigger the control app install.
+  // Trigger the control app install, which will fetch the matching rules.
   external_data_use_observer()
       ->GetDataUseTabModel()
       ->OnControlAppInstallStateChange(true);
   histogram_tester.ExpectTotalCount(kUMAMatchingRuleFirstFetchDurationHistogram,
-                                    0);
+                                    1);
 
   // Verify that matching rules are fetched on the first navigation after the
   // control app is installed.