Add reverse URL handler for shortening uber URLs

content/browser/web_contents/navigation_controller_impl.cc

Index: content/browser/web_contents/navigation_controller_impl.cc
===================================================================
--- content/browser/web_contents/navigation_controller_impl.cc	(revision 156197)
+++ content/browser/web_contents/navigation_controller_impl.cc	(working copy)
@@ -923,11 +923,21 @@
     update_virtual_url = new_entry->update_virtual_url_with_url();
   } else {
     new_entry = new NavigationEntryImpl;
+
+    // Find out whether the new entry needs to update its virtual URL on URL
+    // change and set up the entry accordingly. This is needed to correctly
+    // update the virtual URL when replaceState is called after a pushState.

[Charlie Reis, 2012/09/13 22:10:09]

We were always doing this before, by using true on line 930.  Why do we need to
narrow it to only the cases that RewriteURLIfNecessary sets reverse_on_redirect
to true?  (I find this harder to follow and don't understand the extra
complexity.)

[Cem Kocagil, 2012/09/13 22:40:03]

Actually the only thing that is of importance to me here is the
"set_update_virtual_url_with_url" call. Since I find whether the virtual URL
needs to be updated, I thought I could set "update_virtual_url" to that value
too (instead of always true).

I can revert that line if you want, it doesn't affect the rest of this patch.

[Charlie Reis, 2012/09/13 22:58:23]

Oh, I didn't realize that was the important part.  Feel free to leave the change
to the update_virtual_url line.

Perhaps this would be clearer if you renamed the bool to needs_update? 
(reverse_on_redirect isn't self-evident here.)

+    GURL temp = params.url;

[Charlie Reis, 2012/09/13 22:10:09]

nit: Please use a better variable name than temp.

+    bool reverse_on_redirect = false;
+    BrowserURLHandlerImpl::GetInstance()->RewriteURLIfNecessary(
+        &temp, browser_context_, &reverse_on_redirect);
+    new_entry->set_update_virtual_url_with_url(reverse_on_redirect);
+
     // When navigating to a new page, give the browser URL handler a chance to
     // update the virtual URL based on the new URL. For example, this is needed
     // to show chrome://bookmarks/#1 when the bookmarks webui extension changes
     // the URL.
-    update_virtual_url = true;
+    update_virtual_url = reverse_on_redirect;
   }
 
   new_entry->SetURL(params.url);