Added Client-Hints.

chrome/browser/net/client_hints.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 "chrome/browser/net/client_hints.h"
+
+#include "base/bind.h"
+#include "base/stringprintf.h"
+#include "content/public/browser/browser_thread.h"
+#include "ui/gfx/screen.h"
+
+using base::Bind;
+using content::BrowserThread;

[Ryan Sleevi, 2013/02/26 02:21:04]

These are generally discouraged except when they make significant sense (eg: WK
types). It seems unnecessary here.

[bengr, 2013/02/26 18:19:53]

Done.

+
+namespace {
+typedef base::Callback<void(int, int, float)> ClientHintsCallback;

[Ryan Sleevi, 2013/02/26 02:21:04]

nit: Unused

[bengr, 2013/02/26 18:19:53]

Done.

+
+void FetchScreenInfoOnUIThread(ClientHints::ScreenInfo* info) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  gfx::Display display = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
+  info->width = display.GetSizeInPixel().width();
+  info->height = display.GetSizeInPixel().height();
+  info->pixel_ratio = display.device_scale_factor();
+}
+}  // namespace
+
+ClientHints::ClientHints() : screen_hints_(""), weak_ptr_factory_(this) {
+}
+
+ClientHints::~ClientHints() {
+}
+
+bool ClientHints::RetrieveScreenInfo() {
+  ClientHints::ScreenInfo* info = new ClientHints::ScreenInfo();
+  return BrowserThread::PostTaskAndReply(
+      BrowserThread::UI,
+      FROM_HERE,
+      Bind(&FetchScreenInfoOnUIThread, info),
+      Bind(&ClientHints::UpdateScreenInfo, weak_ptr_factory_.GetWeakPtr(),
+           base::Owned(info)));
+}
+
+std::string ClientHints::GetScreenInfoHints() {
+  return screen_hints_;
+}
+
+void ClientHints::UpdateScreenInfo(ClientHints::ScreenInfo* info) {
+  screen_hints_ = base::StringPrintf(
+      "dh=%d, dw=%d, dpr=%0.3g", info->height, info->width, info->pixel_ratio);
+}
+