Enable the volume slider in Ash for windows.

ash/test/ash_test_helper_unittest.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 "ash/test/ash_test_helper.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/views/widget/widget.h"
 
+#if defined(OS_WIN)
+#include "base/win/windows_version.h"
+#endif
+
 // Tests for AshTestHelper. Who will watch the watchers? And who will test
 // the tests?
 class AshTestHelperTest : public testing::Test {
  public:
   AshTestHelperTest() {}
   virtual ~AshTestHelperTest() {}
 
   virtual void SetUp() OVERRIDE {
     testing::Test::SetUp();
     ash_test_helper_.reset(new ash::test::AshTestHelper(&message_loop_));
@@ skipping 12 matching lines @@
  private:
   base::MessageLoopForUI message_loop_;
   scoped_ptr<ash::test::AshTestHelper> ash_test_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AshTestHelperTest);
 };
 
 // Ensure that we have initialized enough of Ash to create and show a window.
 TEST_F(AshTestHelperTest, AshTestHelper) {
   // Check initial state.
+#if defined(OS_WIN)
+  // Ash doesn't run on versions of Windows prior to Win7.
+  if (base::win::GetVersion() < base::win::VERSION_WIN7)
+    return;
+#endif
   EXPECT_TRUE(ash_test_helper()->message_loop());
   EXPECT_TRUE(ash_test_helper()->test_shell_delegate());
   EXPECT_TRUE(ash_test_helper()->CurrentContext());
 
   // Enough state is initialized to create a window.
   using views::Widget;
   scoped_ptr<Widget> w1(new Widget);
   Widget::InitParams params;
   params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.context = ash_test_helper()->CurrentContext();
   w1->Init(params);
   w1->Show();
   EXPECT_TRUE(w1->IsActive());
   EXPECT_TRUE(w1->IsVisible());
 }