Enable webaudio unit tests iff ENABLE(WEB_AUDIO).

third_party/WebKit/Source/modules/webaudio/StereoPannerNodeTest.cpp

 // Copyright 2015 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 "config.h"
+#if ENABLE(WEB_AUDIO)
 #include "modules/webaudio/StereoPannerNode.h"
 
 #include "core/testing/DummyPageHolder.h"
 #include "modules/webaudio/OfflineAudioContext.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 
 TEST(StereoPannerNodeTest, StereoPannerLifetime)
 {
     OwnPtr<DummyPageHolder> page = DummyPageHolder::create();
     OfflineAudioContext* context = OfflineAudioContext::create(&page->document(), 2, 1, 48000, ASSERT_NO_EXCEPTION);
     StereoPannerNode* node = context->createStereoPanner(ASSERT_NO_EXCEPTION);
     StereoPannerHandler& handler = static_cast<StereoPannerHandler&>(node->handler());
     EXPECT_TRUE(handler.m_stereoPanner);
     AbstractAudioContext::AutoLocker locker(context);
     handler.dispose();
     // m_stereoPanner should live after dispose() because an audio thread is
     // using it.
     EXPECT_TRUE(handler.m_stereoPanner);
 }
 
 } // namespace blink
+
+#endif // ENABLE(WEB_AUDIO)