[WIP]Oilpan: checking for nearly-dead observers.

Source/core/dom/DocumentLifecycleNotifier.cpp

Index: Source/core/dom/DocumentLifecycleNotifier.cpp
diff --git a/Source/core/dom/DocumentLifecycleNotifier.cpp b/Source/core/dom/DocumentLifecycleNotifier.cpp
index 12fc7db522b4032cb733342f5e647fd83d44e211..44222cbab98a677742992ad6cc4fd856f12c7a4d 100644
--- a/Source/core/dom/DocumentLifecycleNotifier.cpp
+++ b/Source/core/dom/DocumentLifecycleNotifier.cpp
@@ -34,16 +34,24 @@ namespace blink {
 void DocumentLifecycleNotifier::notifyDocumentWasDetached()
 {
     TemporaryChange<IterationType> scope(m_iterating, IteratingOverAll);
-    for (DocumentLifecycleObserver* observer : m_observers)
+    for (DocumentLifecycleObserver* observer : m_observers) {
+#if !ENABLE(OILPAN)
+        if (!isObserverAlive(observer))
+            continue;
+#endif
         observer->documentWasDetached();
+    }
 }
 
 #if !ENABLE(OILPAN)
 void DocumentLifecycleNotifier::notifyDocumentWasDisposed()
 {
     TemporaryChange<IterationType> scope(m_iterating, IteratingOverAll);
-    for (DocumentLifecycleObserver* observer : m_observers)
+    for (DocumentLifecycleObserver* observer : m_observers) {
+        if (!isObserverAlive(observer))
+            continue;
         observer->documentWasDisposed();
+    }
 }
 #endif