Metrics for document.write script blocking

third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h

Index: third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h
diff --git a/third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h b/third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h
index be051af21fbc8232b81849372ecca32f638c278b..9b4c2e5b3c07255a52f6e322aaf54d1823709844 100644
--- a/third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h
+++ b/third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h
@@ -18,6 +18,12 @@ enum WebLoadingBehaviorFlag {
     WebLoadingBehaviorDocumentWriteEvaluator = 1 << 0,
     // Indicates that the page is controlled by a Service Worker.
     WebLoadingBehaviorServiceWorkerControlled = 1 << 1,
+    // Indicates that the page has a synchronous, cross-origin document.written
+    // script.
+    WebLoadingBehaviorDocumentWriteBlock = 1 << 1,

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

Looks like you are clobbering WebLoadingBehaviorServiceWorkerControlled (which
should probably have a test to ensure this never happens).

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

My bad. Thanks for catching this. 
I have added a test to check no two values are equal
(DocumentWritePageLoadMetricsObserverTest.ValidFeatureFlags). Only thing I am
concerned about is that  for the test to be extensible to new values , it needs
updation when someone adds a new value to the enum, else it will always pass for
the existing values. I have added a comment to do so.

+    // Indicates that the page is a reload and has a synchronous, cross-origin document.written
+    // script.
+    WebLoadingBehaviorDocumentWriteBlockReload = 1 << 2,
 };
 
 } // namespace blink