WebUI: Fix lifecycle-bug when RenderFrameHost is swapped out

content/browser/webui/web_ui_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_WEBUI_WEB_UI_IMPL_H_
 #define CONTENT_BROWSER_WEBUI_WEB_UI_IMPL_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 18 matching lines @@
 
   // Called when a RenderView is created for a WebUI (reload after a renderer
   // crash) or when a WebUI is created for an RenderView (i.e. navigating from
   // chrome://downloads to chrome://bookmarks) or when both are new (i.e.
   // opening a new tab).
   void RenderViewCreated(RenderViewHost* render_view_host);
 
   // Called when a RenderView is reused for the same WebUI type (i.e. reload).
   void RenderViewReused(RenderViewHost* render_view_host, bool was_main_frame);
 
+  // Called when the owning RenderFrameHost has started swapping out.
+  void RenderFrameHostSwappingOut();
+
   // WebUI implementation:
   WebContents* GetWebContents() const override;
   WebUIController* GetController() const override;
   void SetController(WebUIController* controller) override;
   float GetDeviceScaleFactor() const override;
   const base::string16& GetOverriddenTitle() const override;
   void OverrideTitle(const base::string16& title) override;
   ui::PageTransition GetLinkTransitionType() const override;
   void SetLinkTransitionType(ui::PageTransition type) override;
   int GetBindings() const override;
@@ skipping 70 matching lines @@
   const std::string frame_name_;
 
   std::unique_ptr<WebUIController> controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUIImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEBUI_WEB_UI_IMPL_H_