Add missing ConstrainedDialog code and re-enable disabled PrintPreviewHandlerTest tests on CrOS.

chrome/browser/ui/views/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/tab_contents/tab_contents_wrapper.h"
 #include "chrome/browser/ui/views/tab_contents/tab_contents_container.h"
@@ skipping 104 matching lines @@
   tab_container_->ChangeTabContents(html_tab_contents_->tab_contents());
 
   gfx::Size dialog_size;
   html_delegate_->GetDialogSize(&dialog_size);
   gtk_widget_set_size_request(GetWidgetRoot(),
                               dialog_size.width(),
                               dialog_size.height());
 }
 
 ConstrainedHtmlDelegateGtk::~ConstrainedHtmlDelegateGtk() {
+  if (release_tab_on_close_)
+    ignore_result(html_tab_contents_.release());
 }
 
 HtmlDialogUIDelegate* ConstrainedHtmlDelegateGtk::GetHtmlDialogUIDelegate() {
   return html_delegate_;
 }
 
 void ConstrainedHtmlDelegateGtk::OnDialogCloseFromWebUI() {
   closed_via_webui_ = true;
   window_->CloseConstrainedWindow();
 }
 
 // static
 ConstrainedHtmlUIDelegate* ConstrainedHtmlUI::CreateConstrainedHtmlDialog(
     Profile* profile,
     HtmlDialogUIDelegate* delegate,
     TabContentsWrapper* wrapper) {
   ConstrainedHtmlDelegateGtk* constrained_delegate =
       new ConstrainedHtmlDelegateGtk(profile, delegate);
   ConstrainedWindow* constrained_window =
       new ConstrainedWindowGtk(wrapper, constrained_delegate);
   constrained_delegate->set_window(constrained_window);
   return constrained_delegate;
 }