Metrics for document.write script blocking

chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc

Index: chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc
diff --git a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc b/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc
index 9f0a62790837f35876894e6629950178dd14b04d..47bf6b4aa2b13fa850d54dd3d16346e3209ccd9f 100644
--- a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc
+++ b/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer_unittest.cc
@@ -19,6 +19,8 @@ class DocumentWritePageLoadMetricsObserverTest
   void AssertNoHistogramsLogged() {
     histogram_tester().ExpectTotalCount(
         internal::kHistogramDocWriteParseStartToFirstContentfulPaint, 0);
+    histogram_tester().ExpectTotalCount(
+        internal::kHistogramDocWriteBlockParseStartToFirstContentfulPaint, 0);
   }
 };
 
@@ -63,3 +65,54 @@ TEST_F(DocumentWritePageLoadMetricsObserverTest, NoPossiblePreload) {
   NavigateAndCommit(GURL("https://www.example.com"));
   AssertNoHistogramsLogged();
 }
+
+TEST_F(DocumentWritePageLoadMetricsObserverTest, PossibleBlock) {
+  base::TimeDelta contentful_paint = base::TimeDelta::FromMilliseconds(1);
+  page_load_metrics::PageLoadTiming timing;
+  timing.navigation_start = base::Time::FromDoubleT(1);
+  timing.first_contentful_paint = contentful_paint;
+  timing.parse_start = base::TimeDelta::FromMilliseconds(1);
+  PopulateRequiredTimingFields(&timing);
+
+  page_load_metrics::PageLoadMetadata metadata;
+  metadata.behavior_flags |=
+      blink::WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlock;
+  NavigateAndCommit(GURL("https://www.google.com"));
+  SimulateTimingAndMetadataUpdate(timing, metadata);
+
+  NavigateAndCommit(GURL("https://www.example.com"));
+
+  histogram_tester().ExpectTotalCount(
+      internal::kHistogramDocWriteBlockParseStartToFirstContentfulPaint, 1);
+  histogram_tester().ExpectBucketCount(
+      internal::kHistogramDocWriteBlockParseStartToFirstContentfulPaint,
+      contentful_paint.InMilliseconds(), 1);
+}
+
+TEST_F(DocumentWritePageLoadMetricsObserverTest, PossibleBlockReload) {
+  base::TimeDelta contentful_paint = base::TimeDelta::FromMilliseconds(1);
+  page_load_metrics::PageLoadTiming timing;
+  timing.navigation_start = base::Time::FromDoubleT(1);
+  timing.first_contentful_paint = contentful_paint;
+  timing.parse_start = base::TimeDelta::FromMilliseconds(1);
+  PopulateRequiredTimingFields(&timing);
+
+  page_load_metrics::PageLoadMetadata metadata;
+  metadata.behavior_flags |=
+      blink::WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlockReload;
+  NavigateAndCommit(GURL("https://www.google.com"));
+  SimulateTimingAndMetadataUpdate(timing, metadata);
+
+  NavigateAndCommit(GURL("https://www.example.com"));
+
+  histogram_tester().ExpectTotalCount(
+      internal::kHistogramDocWriteBlockReloadCount, 1);
+
+  // Another reload.
+  NavigateAndCommit(GURL("https://www.google.com"));
+  SimulateTimingAndMetadataUpdate(timing, metadata);
+  NavigateAndCommit(GURL("https://www.example.com"));
+
+  histogram_tester().ExpectTotalCount(
+      internal::kHistogramDocWriteBlockReloadCount, 2);
+}

[Charlie Harrison, 2016/04/29 13:37:53]

Can you add a test that doesn't log any histogram (i.e. assert that the behavior
flag is required)?

[shivanisha, 2016/04/29 15:42:36]

I overloaded the existing test NoPossiblePreload to check that, by adding the
condition in AssertNoHistogramsLogged. I think it will be better to create two
separate assert functions AssertNoPreloadHistogramsLogged and
AssertNoBlockHistogramsLogged. Will do that.