Added Client-Hints.

chrome/browser/net/client_hints.h

Index: chrome/browser/net/client_hints.h
diff --git a/chrome/browser/net/client_hints.h b/chrome/browser/net/client_hints.h
new file mode 100644
index 0000000000000000000000000000000000000000..b61736fb8ba6b48dc4e6c24b89153e6e1a6fffa6
--- /dev/null
+++ b/chrome/browser/net/client_hints.h
@@ -0,0 +1,71 @@
+// 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 CHROME_BROWSER_NET_CLIENT_HINTS_H_
+#define CHROME_BROWSER_NET_CLIENT_HINTS_H_
+
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "base/values.h"
+#include "ui/gfx/rect.h"
+
+struct ScreenHints;
+typedef std::map<std::pair<int, int>, ScreenHints> ScreenMap;

[Ryan Sleevi, 2013/01/17 01:57:56]

nit: Should this be a dependent type of ClientHints, rather than in the global
namespace

ClientHints::ScreenMap

And does this need to be a public type?

[bengr (incorrect), 2013/01/18 02:12:00]

Done.

+
+struct ScreenHints {
+  ScreenHints() :
+      view_bounds(gfx::Rect(0, 0)), device_pixel_ratio(0.0), hints_str("") {}
+  ScreenHints(int width, int height, float d, std::string s) :
+      view_bounds(gfx::Rect(width, height)), device_pixel_ratio(d),
+      hints_str(s) {}
+  gfx::Rect view_bounds;
+  float device_pixel_ratio;
+  std::string hints_str;
+};
+
+namespace content {
+class RenderWidgetHostViewPort;
+}

[Ryan Sleevi, 2013/01/17 01:57:56]

I meant including this forward decl.

Your typedefs and forward decls should appear before your classes.

See
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Declar...

[bengr (incorrect), 2013/01/18 02:12:00]

Done.

+

[Ryan Sleevi, 2013/01/17 01:57:56]

No suitable namespace here? We use chrome_browser_net { } predominantly in here,
it seems.

[bengr (incorrect), 2013/01/18 02:12:00]

Done.

+// 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/master/
+// draft-grigorik-http-client-hints-00.txt
+
+class ClientHints : public base::RefCountedThreadSafe<ClientHints> {
+ public:
+
+  ClientHints();
+
+
+  // Checks to see if screen information is available for the render view with
+  // the given process id and render view id.
+  bool RetrieveScreenInfoIfUnavailable(int process_id, int render_view_id);
+
+  // Returns client hints pertaining to screen information. The format is:
+  // "vh=xx, vw=yy, dpr=zz", where xx, yy, and zz are the viewport height,
+  // viewport width, and device pixel ratio, respectively. These values are the
+  // same as the values returned by the javascript commands:
+  // window.innerHeight, window.innerWidth, and window.devicePixelRatio.
+  // The function should be called only if IsScreenInfoAvailable() returns true.
+  std::string GetScreenInfoHints(int process_id, int render_view_id);
+
+
+ private:
+  friend class ClientHintsTest;
+  friend class base::RefCountedThreadSafe<ClientHints>;
+  ~ClientHints();

[Ryan Sleevi, 2013/01/17 01:57:56]

nit: newline between the friend decls

[bengr (incorrect), 2013/01/18 02:12:00]

Done.

+  bool IsScreenInfoAvailable(int process_id, int render_view_id);
+  void FetchScreenInfoOnUIThread(int process_id, int render_view_id);
+  void UpdateScreenInfo(int process_id, int render_view_id,
+                        int viewport_width, int viewport_height,
+                        float device_pixel_ratio);
+
+  ScreenMap screen_hints_;
+
+  DISALLOW_COPY_AND_ASSIGN(ClientHints);
+};
+
+#endif  // CHROME_BROWSER_NET_CLIENT_HINTS_H_