Reapply and fix r73019. BalloonViewImpl has a different implemementation on

chrome/browser/notifications/balloon_collection_linux.cc

 // 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/notifications/balloon_collection_impl.h"
 
 #include "chrome/browser/notifications/balloon.h"
+#include "gfx/size.h"
+
+#if defined(TOOLKIT_VIEWS)
 #include "chrome/browser/ui/views/notifications/balloon_view.h"
-#include "gfx/size.h"
+#else
+#include "chrome/browser/ui/gtk/notifications/balloon_view_gtk.h"
+#endif
 
 Balloon* BalloonCollectionImpl::MakeBalloon(const Notification& notification,
                                             Profile* profile) {
   Balloon* balloon = new Balloon(notification, profile, this);
 
   balloon->set_view(new BalloonViewImpl(this));
   gfx::Size size(layout_.min_balloon_width(), layout_.min_balloon_height());
   balloon->set_content_size(size);
   return balloon;
 }
@@ skipping 53 matching lines @@
   else
     NOTREACHED();
 
   PositionBalloons(true);
 }
 
 // static
 BalloonCollection* BalloonCollection::Create() {
   return new BalloonCollectionImpl();
 }