Make Pageshow event asynchronous in EventQueueScope

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index e3135f1287c06d78933b25eb417a9570161103b4..abf4836a9dfa17662230ca6846fb32c27f502d83 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -425,7 +425,12 @@ void LocalDOMWindow::EnqueuePageshowEvent(PageshowEventPersistence persisted) {
   // FIXME: https://bugs.webkit.org/show_bug.cgi?id=36334 Pageshow event needs
   // to fire asynchronously.  As per spec pageshow must be triggered
   // asynchronously.  However to be compatible with other browsers blink fires

[tkent, 2017/04/13 01:26:16]

Did you check behavior of latest versions of other browsers?

If some other browsers dispatch it asynchronously, it should be safe to switch
to unconditional asynchronous dispatch.

[tkent, 2017/04/13 06:19:14]

We had offline discussion.
It's too difficult to reproduce synchronous pageshow dispatch even in Chrome.
So, investigating other browsers behavior is also too hard.
We may go ahead with the current approach.  lgtm

-  // pageshow synchronously.
+  // pageshow synchronously unless we are in EventQueueScope.
+  if (ScopedEventQueue::Instance()->ShouldQueueEvents() && document_) {

[yosin_UTC9, 2017/04/12 10:08:03]

Nice finding. I've not known
|(ScopedEventQueue::Instance()->ShouldQueueEvents()|.
(^_^)b

+      EnqueueWindowEvent(
+        PageTransitionEvent::Create(EventTypeNames::pageshow, persisted));
+    return;
+  }
   DispatchEvent(
       PageTransitionEvent::Create(EventTypeNames::pageshow, persisted),
       document_.Get());