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// Copyright 2013 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 CHROME_BROWSER_NET_CLIENT_HINTS_H_
#define CHROME_BROWSER_NET_CLIENT_HINTS_H_
#include <string>
#include "base/basictypes.h"
#include "base/memory/weak_ptr.h"
// ClientHints is a repository in Chrome for information used
// to create the Client-Hints request header. For more information, see:
// https://github.com/igrigorik/http-client-hints/blob/draft2/draft-grigorik-http-client-hints-01.txt
class ClientHints {
public:
static const char kDevicePixelRatioHeader[];
ClientHints();
~ClientHints();
void Init();
// Returns the device pixel ratio as a string. Its value is the same as
// window.devicePixelRatio in Javascript.
const std::string& GetDevicePixelRatioHeader() const;
private:
friend class ClientHintsTest;
// Retrieves and updates screen information for use on the IO thread.
bool RetrieveScreenInfo();
void UpdateScreenInfo(float device_pixel_ratio_value);
std::string screen_hints_;
base::WeakPtrFactory<ClientHints> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(ClientHints);
};
#endif // CHROME_BROWSER_NET_CLIENT_HINTS_H_
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