Make ApplicationCache a DOMWindowClient

third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp

Index: third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp
diff --git a/third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp b/third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp
index b521bd9b6d10e72c364100909d10d162c38536c1..ad3976086d82c97ba1c98609ae7c91d83028c3f5 100644
--- a/third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp
+++ b/third_party/WebKit/Source/core/loader/appcache/ApplicationCacheHost.cpp
@@ -260,11 +260,12 @@ void ApplicationCacheHost::dispatchDOMEvent(
     const String& errorURL,
     int errorStatus,
     const String& errorMessage) {
-  if (!m_domApplicationCache)
+  // Don't dispatch an event if the window is detached.
+  if (!m_domApplicationCache || !m_domApplicationCache->domWindow())
     return;
 
   const AtomicString& eventType = ApplicationCache::toEventType(id);
-  if (eventType.isEmpty() || !m_domApplicationCache->getExecutionContext())
+  if (eventType.isEmpty())
     return;
   Event* event = nullptr;
   if (id == kProgressEvent) {