Move PageTransition into content namespace. While I'm touching all these files, I've also updated...

chrome/browser/ui/gtk/constrained_html_delegate_gtk.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/ui/webui/constrained_html_ui.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/gtk/constrained_window_gtk.h"
 #include "chrome/browser/ui/gtk/tab_contents_container_gtk.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
@@ skipping 67 matching lines @@
       window_(NULL),
       closed_via_webui_(false) {
   tab_.tab_contents()->set_delegate(this);
 
   // Set |this| as a property on the tab contents so that the ConstrainedHtmlUI
   // can get a reference to |this|.
   ConstrainedHtmlUI::GetPropertyAccessor().SetProperty(
       tab_.tab_contents()->property_bag(), this);
 
   tab_.tab_contents()->controller().LoadURL(
-      delegate->GetDialogContentURL(), GURL(), PageTransition::START_PAGE,
-      std::string());
+      delegate->GetDialogContentURL(), GURL(),
+      content::PAGE_TRANSITION_START_PAGE, std::string());
   tab_contents_container_.SetTab(&tab_);
 
   gfx::Size dialog_size;
   delegate->GetDialogSize(&dialog_size);
   gtk_widget_set_size_request(GTK_WIDGET(tab_contents_container_.widget()),
                               dialog_size.width(),
                               dialog_size.height());
 
   gtk_widget_show_all(GetWidgetRoot());
 }
@@ skipping 16 matching lines @@
     Profile* profile,
     HtmlDialogUIDelegate* delegate,
     TabContentsWrapper* overshadowed) {
   ConstrainedHtmlDelegateGtk* constrained_delegate =
       new ConstrainedHtmlDelegateGtk(profile, delegate);
   ConstrainedWindow* constrained_window =
       new ConstrainedWindowGtk(overshadowed, constrained_delegate);
   constrained_delegate->set_window(constrained_window);
   return constrained_window;
 }