destroy guest webcontents before embedder

atom/browser/api/atom_api_web_contents.cc

@@ -411,14 +411,18 @@ WebContents::~WebContents() {
     if (type_ == WEB_VIEW)
       guest_delegate_->Destroy();
 
-    // The WebContentsDestroyed will not be called automatically because we
-    // unsubscribe from webContents before destroying it. So we have to manually
-    // call it here to make sure "destroyed" event is emitted.
     RenderViewDeleted(web_contents()->GetRenderViewHost());
-    WebContentsDestroyed();
+    DestroyWebContents();
   }
 }
 
+void WebContents::DestroyWebContents() {
+  // This event is only for internal use, which is emitted when WebContents is
+  // being destroyed.
+  Emit("will-destroy");
+  CommonWebContentsDelegate::DestroyWebContents();
+}
+
 bool WebContents::DidAddMessageToConsole(content::WebContents* source,
                                          int32_t level,
                                          const base::string16& message,
@@ -919,10 +923,6 @@ bool WebContents::OnMessageReceived(const IPC::Message& message) {
 // be destroyed on close, and WebContentsDestroyed would be called for it, so
 // we need to make sure the api::WebContents is also deleted.
 void WebContents::WebContentsDestroyed() {
-  // This event is only for internal use, which is emitted when WebContents is
-  // being destroyed.
-  Emit("will-destroy");
-
   // Cleanup relationships with other parts.
   RemoveFromWeakMap();
 

atom/browser/api/atom_api_web_contents.h

@@ -76,6 +76,9 @@ class WebContents : public mate::TrackableObject<WebContents>,
   static void BuildPrototype(v8::Isolate* isolate,
                              v8::Local<v8::FunctionTemplate> prototype);
 
+  // Notifies to destroy any guest web contents before destroying self.
+  void DestroyWebContents();
+
   int64_t GetID() const;
   int GetProcessID() const;
   Type GetType() const;