Metrics for document.write script blocking

chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h b/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
index a24421b2e7a2fed61f9494562618d791f1c18bf3..28fbd170fb3714ec447e7e846a06d20e0c9b6fb1 100644
--- a/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h
@@ -10,8 +10,10 @@
 
 namespace internal {
 
-// Just expose one metric for tests.
+// Just expose one metric per feature for tests.
 extern const char kHistogramDocWriteParseStartToFirstContentfulPaint[];
+extern const char kHistogramDocWriteBlockParseStartToFirstContentfulPaint[];
+extern const char kHistogramDocWriteBlockReloads[];
 
 }  // namespace internal
 
@@ -29,6 +31,10 @@ class DocumentWritePageLoadMetricsObserver
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info);
 
+  void LogDocumentWriteBlockData(
+      const page_load_metrics::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& info);
+
   DISALLOW_COPY_AND_ASSIGN(DocumentWritePageLoadMetricsObserver);
 };