Move remaining content test code into the content namespace.

content/test/mock_keyboard.cc

 // Copyright (c) 2011 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/mock_keyboard.h"
 
 #include "base/logging.h"
 
+namespace content {
+
 MockKeyboard::MockKeyboard()
     : keyboard_layout_(LAYOUT_NULL),
       keyboard_modifiers_(INVALID) {
 }
 
 MockKeyboard::~MockKeyboard() {
 }
 
 int MockKeyboard::GetCharacters(Layout layout,
                                 int key_code,
@@ skipping 19 matching lines @@
     keyboard_modifiers_ = modifiers;
   }
 
   // Retrieve Unicode characters associate with the key code.
   return driver_.GetCharacters(key_code, output);
 #else
   NOTIMPLEMENTED();
   return -1;
 #endif
 }
+
+}  // namespace content