Fix utterly wrong comment that hasn't been true for years.

content/public/browser/navigation_controller.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_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/string16.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/global_request_id.h"
 #include "content/public/common/page_transition_types.h"
 
 class GURL;
 
 namespace content {
 
 class BrowserContext;
 class NavigationEntry;
 class SessionStorageNamespace;
 class WebContents;
 struct Referrer;
 
 // A NavigationController maintains the back-forward list for a single tab and
 // manages all navigation within that list.
 //
-// The NavigationController also owns all WebContents for the tab. This is to
-// make sure that we have at most one WebContents instance per type.
+// Each NavigationController belongs to one WebContents; each WebContents has
+// exactly one NavigationController.
 class NavigationController {
  public:
   enum ReloadType {
     NO_RELOAD,                // Normal load.
     RELOAD,                   // Normal (cache-validating) reload.
     RELOAD_IGNORING_CACHE     // Reload bypassing the cache, aka shift-reload.
   };
 
   // Creates navigation entry and translates the virtual url to a real one.
   // Used when navigating to a new URL using LoadURL.  Extra headers are
   // separated by \n.
   CONTENT_EXPORT static NavigationEntry* CreateNavigationEntry(
       const GURL& url,
       const Referrer& referrer,
       PageTransition transition,
       bool is_renderer_initiated,
       const std::string& extra_headers,
       BrowserContext* browser_context);
 
   // Disables checking for a repost and prompting the user. This is used during
   // testing.
   CONTENT_EXPORT static void DisablePromptOnRepost();
 
   virtual ~NavigationController() {}
 
   // Returns the web contents associated with this controller. Non-NULL except
-  // during set-up of the tab.
+  // during set-up.

[jochen (gone - plz use gerrit), 2012/05/24 21:38:55]

is this true? I thought this is just implemented as return web_contents_ which
is initialized in NavigationControllerImpl's constructor

   virtual WebContents* GetWebContents() const = 0;
 
   // Get/set the browser context for this controller. It can never be NULL.
   virtual BrowserContext* GetBrowserContext() const = 0;
   virtual void SetBrowserContext(BrowserContext* browser_context) = 0;
 
   // Initializes this NavigationController with the given saved navigations,
   // using selected_navigation as the currently loaded entry. Before this call
   // the controller should be unused (there should be no current entry). If
   // from_last_session is true, navigations are from the previous session,
@@ skipping 180 matching lines @@
   virtual void CopyStateFromAndPrune(NavigationController* source) = 0;
 
   // Removes all the entries except the active entry. If there is a new pending
   // navigation it is preserved.
   virtual void PruneAllButActive() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_