Reland #2 of: Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.

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 <set>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_ui.h"
 #include "ipc/ipc_listener.h"
 
 namespace content {
 class RenderFrameHost;
 class RenderViewHost;
 
 class CONTENT_EXPORT WebUIImpl : public WebUI,
                                  public IPC::Listener,
                                  public base::SupportsWeakPtr<WebUIImpl> {
  public:
   WebUIImpl(WebContents* contents, const std::string& frame_name);
   ~WebUIImpl() override;
 
-  // Called by WebContentsImpl when the RenderView is first created. This is
-  // *not* called for every page load because in some cases
-  // RenderFrameHostManager will reuse RenderView instances.
+  // 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 by WebContentsImpl when the RenderView is reused. This happens on
-  // refresh or when the main page is navigated within the same SiteInstance.
+  // Called when a RenderView is reused for the same WebUI type (i.e. reload).
   void RenderViewReused(RenderViewHost* render_view_host, bool was_main_frame);
 
   // 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;
@@ skipping 71 matching lines @@
   const std::string frame_name_;
 
   scoped_ptr<WebUIController> controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUIImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEBUI_WEB_UI_IMPL_H_