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

chrome/browser/ui/gtk/html_dialog_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/gtk/html_dialog_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 148 matching lines @@
   tab_.reset(new TabContentsWrapper(
       new TabContents(profile(), NULL, MSG_ROUTING_NONE, NULL, NULL)));
   tab_->tab_contents()->set_delegate(this);
 
   // This must be done before loading the page; see the comments in
   // HtmlDialogUI.
   HtmlDialogUI::GetPropertyAccessor().SetProperty(
       tab_->tab_contents()->property_bag(), this);
 
   tab_->controller().LoadURL(GetDialogContentURL(),
-                             GURL(), PageTransition::START_PAGE, std::string());
+                             GURL(), content::PAGE_TRANSITION_START_PAGE,
+                             std::string());
   GtkDialogFlags flags = GTK_DIALOG_NO_SEPARATOR;
   if (delegate_->IsDialogModal())
     flags = static_cast<GtkDialogFlags>(flags | GTK_DIALOG_MODAL);
 
   dialog_ = gtk_dialog_new_with_buttons(
       UTF16ToUTF8(delegate_->GetDialogTitle()).c_str(),
       parent_window_,
       flags,
       NULL);
 
@@ skipping 15 matching lines @@
                               dialog_size.height());
 
   gtk_widget_show_all(dialog_);
 
   return GTK_WINDOW(dialog_);
 }
 
 void HtmlDialogGtk::OnResponse(GtkWidget* dialog, int response_id) {
   OnDialogClosed(std::string());
 }