Use a direct include of strings headers in ppapi/, printing/.

ppapi/shared_impl/ppb_gamepad_shared.h

 // 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.
 
 #ifndef PPAPI_SHARED_IMPL_PPB_GAMEPAD_SHARED_H_
 #define PPAPI_SHARED_IMPL_PPB_GAMEPAD_SHARED_H_
 
 #include "base/atomicops.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ppapi/c/ppb_gamepad.h"
 #include "ppapi/shared_impl/ppapi_shared_export.h"
 
 namespace ppapi {
 
 // TODO(brettw) when we remove the non-IPC-based gamepad implementation, this
 // code should all move into the GamepadResource.
 
 #pragma pack(push, 1)
 
@@ skipping 49 matching lines @@
 
 #pragma pack(pop)
 
 PPAPI_SHARED_EXPORT void ConvertWebKitGamepadData(
     const WebKitGamepads& webkit_data,
     PP_GamepadsSampleData* output_data);
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_PPB_GAMEPAD_SHARED_H_