Performance: Respect navigation's AllowTimingDetails() override in workerStart().

This change means we will now properly populate workerStart on the
PerformanceNavigationTiming entry.  Previously it was always being set
to zero.

Bug: 1044810
Change-Id: Idca297222a36dfb54a6ad84e1414267cfff56aa6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2043932Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
Commit-Queue: Ben Kelly <wanderview@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739465}

third_party/blink/renderer/core/timing/performance_resource_timing.cc

@@ -178,7 +178,7 @@ bool IsDocumentDestination(mojom::RequestContextType context_type) {
 DOMHighResTimeStamp PerformanceResourceTiming::workerStart() const {
   ResourceLoadTiming* timing = GetResourceLoadTiming();
   if (!timing || timing->WorkerStart().is_null() ||
-      (!allow_timing_details_ && IsDocumentDestination(context_type_))) {
+      (!AllowTimingDetails() && IsDocumentDestination(context_type_))) {
     return 0.0;
   }
 

third_party/blink/renderer/core/timing/performance_resource_timing.h

@@ -133,6 +133,8 @@ class CORE_EXPORT PerformanceResourceTiming
   uint64_t encoded_body_size_ = 0;
   uint64_t decoded_body_size_ = 0;
   bool did_reuse_connection_ = false;
+  // Do not access allow_timing_details_ directly.  Instead use the
+  // AllowTimingDetails() method which is overridden by some sub-classes.
   bool allow_timing_details_ = false;
   bool allow_redirect_details_ = false;
   bool allow_negative_value_ = false;

third_party/blink/web_tests/external/wpt/service-workers/service-worker/navigation-timing.https.html

@@ -46,6 +46,7 @@ promise_test(t => {
         return navigate_in_frame(frame, 'resources/empty.html');
       })
       .then(timing => {
+        assert_greater_than(timing.workerStart, 0);
         verify(timing);
       })
       .catch(unreached_rejection(t))