Move remaining content test code into the content namespace.

content/browser/audio_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 "content/test/layout_browsertest.h"
 
+namespace content {
+
 class AudioLayoutTest : public InProcessBrowserLayoutTest {
  protected:
   AudioLayoutTest() : InProcessBrowserLayoutTest(
       FilePath(), FilePath().AppendASCII("media")) {
   }
 };
 
 IN_PROC_BROWSER_TEST_F(AudioLayoutTest, AudioConstructorPreload) {
   RunLayoutTest("audio-constructor-preload.html");
 }
@@ skipping 35 matching lines @@
   RunLayoutTest("audio-play-event.html");
 }
 
 IN_PROC_BROWSER_TEST_F(AudioLayoutTest, MediaCanPlayWavAudio) {
   RunLayoutTest("media-can-play-wav-audio.html");
 }
 
 IN_PROC_BROWSER_TEST_F(AudioLayoutTest, MediaDocumentAudioSize) {
   RunLayoutTest("media-document-audio-size.html");
 }
+
+}  // namespace content