Add UMA for network type at request start

components/offline_pages/core/background/request_coordinator_unittest.cc

Index: components/offline_pages/core/background/request_coordinator_unittest.cc
diff --git a/components/offline_pages/core/background/request_coordinator_unittest.cc b/components/offline_pages/core/background/request_coordinator_unittest.cc
index 5933792f28b5e73907a93fb8132e263b94a9ac46..8bdbba12bd72c3967752b5134d6372727e466c2b 100644
--- a/components/offline_pages/core/background/request_coordinator_unittest.cc
+++ b/components/offline_pages/core/background/request_coordinator_unittest.cc
@@ -784,6 +784,12 @@ TEST_F(RequestCoordinatorTest, OfflinerDoneRequestFailedNoRetryFailure) {
   EXPECT_TRUE(observer().completed_called());
   EXPECT_EQ(RequestCoordinator::BackgroundSavePageResult::LOADING_FAILURE,
             observer().last_status());
+  // We should have a histogram entry for the effective network conditions
+  // when this failed request began.
+  histograms().ExpectBucketCount(
+      "OfflinePages.Background.EffectiveConnectionType.OffliningStartType."
+      "bookmark",
+      net::NetworkChangeNotifier::CONNECTION_UNKNOWN, 1);
 }
 
 TEST_F(RequestCoordinatorTest, OfflinerDoneRequestFailedNoNextFailure) {