Clean up ownership in WebUI creation.

chrome/browser/ui/webui/uber/uber_ui.h

Index: chrome/browser/ui/webui/uber/uber_ui.h
diff --git a/chrome/browser/ui/webui/uber/uber_ui.h b/chrome/browser/ui/webui/uber/uber_ui.h
index f3c2107a02d0e25f3ea401396f309349bd56af60..05e799a6945738496c67b10e545a7bd4989fe9bb 100644
--- a/chrome/browser/ui/webui/uber/uber_ui.h
+++ b/chrome/browser/ui/webui/uber/uber_ui.h
@@ -57,17 +57,14 @@ class UberUI : public content::WebUIController {
   void RenderViewCreated(content::RenderViewHost* render_view_host) override;
 
  private:
-  // A map from URL origin to WebUI instance.
-  typedef std::map<std::string, content::WebUI*> SubpageMap;
-
   // Creates and stores a WebUI for the given URL.
   void RegisterSubpage(const std::string& page_url,
                        const std::string& page_host);
 
   SubframeLogger subframe_logger_;
 
-  // The WebUI*s in this map are owned.
-  SubpageMap sub_uis_;
+  // Map from URL origin to WebUI instance.
+  std::map<std::string, std::unique_ptr<content::WebUI>> sub_uis_;
 
   DISALLOW_COPY_AND_ASSIGN(UberUI);
 };