Put common code of OpenURLFromTab to CommonWebContentsDelegate

atom/browser/common_web_contents_delegate.h

@@ -48,6 +48,9 @@ class CommonWebContentsDelegate
 
  protected:
   // content::WebContentsDelegate:
+  content::WebContents* OpenURLFromTab(
+      content::WebContents* source,
+      const content::OpenURLParams& params) override;
   void RequestToLockMouse(content::WebContents* web_contents,
                           bool user_gesture,
                           bool last_unlocked_by_target) override;