Adds testing infrastructure to web_ui_browsertest to support testing HtmlDialogs.

chrome/test/base/test_html_dialog_observer.h

Index: chrome/test/base/test_html_dialog_observer.h
diff --git a/chrome/test/base/test_html_dialog_observer.h b/chrome/test/base/test_html_dialog_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..e2188c34b5fc4153cd92555f1a7930e0690730dd
--- /dev/null
+++ b/chrome/test/base/test_html_dialog_observer.h
@@ -0,0 +1,42 @@
+// 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.
+
+#ifndef CHROME_TEST_BASE_TEST_HTML_DIALOG_OBSERVER_H_
+#define CHROME_TEST_BASE_TEST_HTML_DIALOG_OBSERVER_H_
+#pragma once
+
+#include "base/compiler_specific.h"
+#include "content/common/notification_observer.h"
+#include "content/common/notification_registrar.h"
+
+class WebUI;
+
+// For browser_tests, which run on the UI thread, run a second message
+// MessageLoop to detect HtmlDialog creation and quit when the constructed
+// WebUI instance is captured and ready.
+class TestHtmlDialogObserver : public NotificationObserver {
+ public:
+  // Create and register a new TestHtmlDialogObserver.
+  TestHtmlDialogObserver();
+  virtual ~TestHtmlDialogObserver();
+
+  // Waits for an HtmlDialog to be created. The WebUI instance is captured
+  // and the method returns it when the navigation on the dialog is complete.
+  WebUI* GetWebUI();
+
+ private:
+  // NotificationObserver:
+  virtual void Observe(int type, const NotificationSource& source,
+                       const NotificationDetails& details) OVERRIDE;
+
+  NotificationRegistrar registrar_;
+
+  WebUI* web_ui_;
+  bool done_;
+  bool running_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestHtmlDialogObserver);
+};
+
+#endif  // CHROME_TEST_BASE_TEST_HTML_DIALOG_OBSERVER_H_