[subresource_filter] Use the SubresourceFilterObserver for PageLoadMetrics

chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc

Index: chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc
diff --git a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc
index c9eb705d09b55a66fdbfe2c6543fc048b8d0428f..5dac13b1b425eb7afcf42d2f60fd9c6f003780a7 100644
--- a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc
+++ b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer_unittest.cc
@@ -18,10 +18,10 @@ class SubresourceFilterMetricsObserverTest
     tracker->AddObserver(base::MakeUnique<SubresourceFilterMetricsObserver>());
   }
 
-  bool AnyMetricsRecorded() {
-    return !histogram_tester()
-                .GetTotalCountsForPrefix("PageLoad.Clients.SubresourceFilter.")
-                .empty();
+  size_t TotalMetricsRecorded() {
+    return histogram_tester()
+        .GetTotalCountsForPrefix("PageLoad.Clients.SubresourceFilter.")
+        .size();
   }
 
   void InitializePageLoadTiming(
@@ -58,7 +58,7 @@ TEST_F(SubresourceFilterMetricsObserverTest,
   // metrics.
   NavigateToUntrackedUrl();
 
-  ASSERT_FALSE(AnyMetricsRecorded());
+  EXPECT_EQ(0u, TotalMetricsRecorded());
 }
 
 TEST_F(SubresourceFilterMetricsObserverTest, Basic) {
@@ -74,7 +74,7 @@ TEST_F(SubresourceFilterMetricsObserverTest, Basic) {
   // Navigate away from the current page to force logging of metrics.
   NavigateToUntrackedUrl();
 
-  ASSERT_TRUE(AnyMetricsRecorded());
+  EXPECT_GT(TotalMetricsRecorded(), 0u);
 
   histogram_tester().ExpectTotalCount(
       internal::kHistogramSubresourceFilterCount, 1);