Change NavigationController::LoadURL to take a Referrer class instead of a GURL as referrer

chrome/browser/ui/cocoa/notifications/balloon_controller.mm

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/ui/cocoa/notifications/balloon_controller.h"
 
 #import "base/mac/cocoa_protocols.h"
 #include "base/mac/mac_util.h"
 #import "base/memory/scoped_nsobject.h"
 #include "base/utf_string_conversions.h"
@@ skipping 159 matching lines @@
     delayedClose_ = YES;
     return;
   }
   [self closeBalloonNow: byUser];
 }
 
 - (void)updateContents {
   DCHECK(htmlContents_.get()) << "BalloonView::Update called before Show";
   if (htmlContents_->tab_contents()) {
     htmlContents_->tab_contents()->controller().LoadURL(
-        balloon_->notification().content_url(), GURL(),
+        balloon_->notification().content_url(), content::Referrer(),
         content::PAGE_TRANSITION_LINK, std::string());
   }
 }
 
 - (void)repositionToBalloon {
   DCHECK(balloon_);
   int x = balloon_->GetPosition().x();
   int y = balloon_->GetPosition().y();
   int w = [self desiredTotalWidth];
   int h = [self desiredTotalHeight];
@@ skipping 26 matching lines @@
   htmlContents_.reset(new BalloonViewHost(balloon_));
   htmlContents_->Init();
 }
 
 // NSWindowDelegate notification.
 - (void)windowWillClose:(NSNotification*)notif {
   [self autorelease];
 }
 
 @end