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

content/public/browser/navigation_controller.h

Index: content/public/browser/navigation_controller.h
diff --git a/content/public/browser/navigation_controller.h b/content/public/browser/navigation_controller.h
index 4829349e8930ebc4eb0eb4a4fe488833dcb57011..c9c1a01384a76cd56736af5fe1bc2e9e5c4ec4fd 100644
--- a/content/public/browser/navigation_controller.h
+++ b/content/public/browser/navigation_controller.h
@@ -24,11 +24,11 @@ class SessionStorageNamespace;
 class WebContents;
 struct Referrer;
 
-// A NavigationController maintains the back-forward list for a single tab and
+// A NavigationController maintains the back-forward list for a WebContents 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 {
@@ -37,9 +37,9 @@ class NavigationController {
     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.
+  // Creates a navigation entry and translates the virtual url to a real one.
+  // This is a general call; prefer LoadURL[FromRenderer]/TransferURL below.
+  // Extra headers are separated by \n.
   CONTENT_EXPORT static NavigationEntry* CreateNavigationEntry(
       const GURL& url,
       const Referrer& referrer,
@@ -54,8 +54,8 @@ class NavigationController {
 
   virtual ~NavigationController() {}
 
-  // Returns the web contents associated with this controller. Non-NULL except
-  // during set-up of the tab.
+  // Returns the web contents associated with this controller. It can never be
+  // NULL.
   virtual WebContents* GetWebContents() const = 0;
 
   // Get/set the browser context for this controller. It can never be NULL.
@@ -73,6 +73,17 @@ class NavigationController {
                        bool from_last_session,
                        std::vector<NavigationEntry*>* entries) = 0;
 
+  // Entries -------------------------------------------------------------------
+
+  // There are two basic states for entries: pending and committed. When an
+  // entry is navigated to, a request is sent to the server. While that request
+  // has not been responded to, the NavigationEntry is pending. Once data is
+  // received for that entry, that NavigationEntry is committed.
+
+  // A transient entry is an entry that, when the user navigates away, is
+  // removed and discarded rather than being added to the back-forward list.
+  // Transient entries are useful for interstitial pages and the like.
+
   // Active entry --------------------------------------------------------------
 
   // Returns the active entry, which is the transient entry if any, the pending