Clean up ownership in WebUI creation.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index 7eaa25270321d1547375d50b2941abfcbeccec81..6edb0ac5b823f7a23798204f80d43503115dbe25 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <set>
 
 #include "base/callback_forward.h"
@@ -293,8 +294,9 @@ class WebContents : public PageNavigator,
   // necessary. However if the embedder wants to create its own WebUI object and
   // keep track of it manually, it can use this. |frame_name| is used to
   // identify the frame and cannot be empty.
-  virtual WebUI* CreateSubframeWebUI(const GURL& url,
-                                     const std::string& frame_name) = 0;
+  virtual std::unique_ptr<WebUI> CreateSubframeWebUI(
+      const GURL& url,
+      const std::string& frame_name) = 0;
 
   // Returns the committed WebUI if one exists, otherwise the pending one.
   virtual WebUI* GetWebUI() const = 0;