Fixes content_browsertests with --enable-text-input-focus-manager flag enabled.

content/shell/browser/shell_views.cc

 // Copyright 2013 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 "content/shell/browser/shell.h"
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/context_factory.h"
 #include "content/public/browser/render_widget_host_view.h"
@@ skipping 419 matching lines @@
 #else
   gfx::Screen::SetScreenInstance(
       gfx::SCREEN_TYPE_NATIVE, views::CreateDesktopScreen());
 #endif
   views_delegate_ = new ShellViewsDelegateAura();
 }
 
 void Shell::PlatformExit() {
 #if defined(OS_CHROMEOS)
   delete wm_test_helper_;
+  wm_test_helper_ = NULL;
 #endif
   delete views_delegate_;
   views_delegate_ = NULL;
   delete platform_;
   platform_ = NULL;
 #if defined(OS_CHROMEOS)
   chromeos::DBusThreadManager::Shutdown();
 #endif
   aura::Env::DeleteInstance();
 }
@@ skipping 113 matching lines @@
 
 void Shell::PlatformWebContentsFocused(WebContents* contents) {
   if (headless_)
     return;
   ShellWindowDelegateView* delegate_view =
     static_cast<ShellWindowDelegateView*>(window_widget_->widget_delegate());
   delegate_view->OnWebContentsFocused(contents);
 }
 
 }  // namespace content