Bug 1132874 - Improve PPluginWidget shutdown logic. r=aklotz

widget/PluginWidgetProxy.cpp

@@ -38,7 +38,7 @@ PluginWidgetProxy::PluginWidgetProxy(dom::TabChild* aTabChild,
   mActor(aActor)
 {
   // See ChannelDestroyed() in the header
-  mActor->mWidget = this;
+  mActor->SetWidget(this);
 }
 
 PluginWidgetProxy::~PluginWidgetProxy()
@@ -99,22 +99,9 @@ PluginWidgetProxy::Destroy()
   PWLOG("PluginWidgetProxy::Destroy()\n");
 
   if (mActor) {
-   /**
-    * We need to communicate that the sub protocol is going to be torn down
-    * before the sub protocol dies. Otherwise we can end up with async events
-    * in transit from chrome to content, which on arrival will trigger an abort
-    * in the content process, crashing all tabs.
-    *
-    * Note, this is one of two ways PluginWidget tear down initiates. Here we
-    * are a plugin in content and content has just unloaded us for some reason,
-    * usually due to swap out for flash ads or the user simply loaded a
-    * different page. The other involves a full tear down of the tab (PBrowser)
-    * which happens prior to widgets getting collected by ref counting in
-    * layout. We still get this Destroy call, but in all likelyhood mActor is
-    * already null via a call on ChannelDestroyed from PluginWidgetChild.
-    */
-    mActor->SendDestroy();
-    mActor->mWidget = nullptr;
+    // Communicate that the layout widget has been torn down before the sub
+    // protocol.
+    mActor->ProxyShutdown();
     mActor = nullptr;
   }