Transitively keep track of an isolated world's children scripts and worlds.

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

Index: third_party/WebKit/Source/core/frame/DOMTimer.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMTimer.cpp b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
index 78da1a72b2de6f537282463ed404223098a766dc..84b161db4c8586a784de859e82c2fc419248baad 100644
--- a/third_party/WebKit/Source/core/frame/DOMTimer.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
@@ -72,6 +72,10 @@ DOMTimer::DOMTimer(ExecutionContext* context, PassOwnPtrWillBeRawPtr<ScheduledAc
     , m_nestingLevel(context->timers()->timerNestingLevel() + 1)
     , m_action(action)
 {
+    // Store the creating worldId, as the timer is fired in the main world.
+    ASSERT(v8::Isolate::GetCurrent()->InContext());
+    m_originWorld = PassRefPtr<DOMWrapperWorld>(DOMWrapperWorld::current(v8::Isolate::GetCurrent()).originWorld());

[haraken, 2016/01/21 10:16:15]

Ditto.

+
     ASSERT(timeoutID > 0);
     if (shouldForwardUserGesture(interval, m_nestingLevel))
         m_userGestureToken = UserGestureIndicator::currentToken();
@@ -104,6 +108,8 @@ void DOMTimer::fired()
     ASSERT(!context->activeDOMObjectsAreSuspended());
     // Only the first execution of a multi-shot timer should get an affirmative user gesture indicator.
     UserGestureIndicator gestureIndicator(m_userGestureToken.release());
+    // Ensure the origin world is propagated to the action and is reset afterwards.
+    DOMWrapperWorld::OriginWorldPusher worldPusher(ScriptState::forMainWorld(toDocument(context)->frame())->world(), m_originWorld);

[haraken, 2016/01/21 16:41:33]

For example, the world in this first parameter is wrong.
ScriptState::forMainWorld(...)->world() just returns the main world but there is
no guarantee that we are in the main world at this point.

That's why I want to remove the first parameter from the OriginWorldPusher
(rather than trying to make the first parameter correct).

 
     TRACE_EVENT1("devtools.timeline", "TimerFire", "data", InspectorTimerFireEvent::data(context, m_timeoutID));
     InspectorInstrumentationCookie cookie = InspectorInstrumentation::willFireTimer(context, m_timeoutID);