Move a bunch of content\common code into the content namespace.

content/renderer/active_notification_tracker_unittest.cc

 // Copyright (c) 2010 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/renderer/active_notification_tracker.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+namespace content {
+
 TEST(ActiveNotificationTrackerTest, TestLookupAndClear) {
   ActiveNotificationTracker tracker;
 
   WebKit::WebNotification notification1;
   int id1 = tracker.RegisterNotification(notification1);
 
   WebKit::WebNotification notification2;
   int id2 = tracker.RegisterNotification(notification2);
 
   WebKit::WebNotification result;
   tracker.GetNotification(id1, &result);
   EXPECT_TRUE(result == notification1);
 
   tracker.GetNotification(id2, &result);
   EXPECT_TRUE(result == notification2);
 
   tracker.Clear();
 }
+
+}  // namespace content