No issue - Align our resource timing with the updated Fetch spec.

This makes FetchStart use StartTime() when the TAO check fails for
PerformanceResourceTiming

Given the recent Fetch spec updates, Step 8.1 in
https://fetch.spec.whatwg.org/#finalize-and-report-timing specifies that start
time(StartTime) and post-redirect start time(FetchStart) should be start time
when the TAO check fails.

1 files changed, 5 insertions, 2 deletions

diff --git a/dom/performance/PerformanceResourceTiming.h b/dom/performance/PerformanceResourceTiming.h
index 61ad8f0c65..b4775d4322 100644
--- a/dom/performance/PerformanceResourceTiming.h
+++ b/dom/performance/PerformanceResourceTiming.h
@@ -69,9 +69,12 @@ public:
   }
 
   DOMHighResTimeStamp FetchStart() const {
-    return mTiming
+    if (mTiming) {
+      return mTiming->TimingAllowed()
         ? mTiming->FetchStartHighRes()
-        : 0;
+        : StartTime();
+    }
+    return 0;
   }
 
   DOMHighResTimeStamp RedirectStart() const {