Abstract WebContentsObserver from Autofill shared code

chrome/browser/autofill/autofill_external_delegate_browsertest.cc

 // Copyright (c) 2012 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 "base/memory/scoped_ptr.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/testing_pref_service_syncable.h"
 #include "components/autofill/browser/autofill_manager.h"
 #include "components/autofill/browser/test_autofill_external_delegate.h"
 #include "components/autofill/browser/test_autofill_manager_delegate.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/page_navigator.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/test/test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/rect.h"
 
 namespace autofill {
 namespace {
 
 class MockAutofillManagerDelegate
@@ skipping 122 matching lines @@
   browser()->OpenURL(content::OpenURLParams(
       GURL(chrome::kChromeUIBookmarksURL), content::Referrer(),
       CURRENT_TAB, content::PAGE_TRANSITION_TYPED, false));
   browser()->OpenURL(content::OpenURLParams(
       GURL(chrome::kChromeUIAboutURL), content::Referrer(),
       CURRENT_TAB, content::PAGE_TRANSITION_TYPED, false));
   observer.Wait();
 }
 
 }  // namespace autofill