linux_aura: Implement most of DesktopScreenX11.

base/x11/edid_parser_x11.h

+// Copyright (c) 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 BASE_X11_EDID_PARSER_X11_H_
+#define BASE_X11_EDID_PARSER_X11_H_
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+
+typedef unsigned long XID;

[brettw, 2013/09/21 05:19:27]

Can you add a comment near the top somewhere saying what an EDID is? I doubt
most people have heard of it.

+
+namespace base {
+
+// Get the EDID data from the |output| and stores to |prop|. |nitem| will store
+// the number of characters |prop| will have. It doesn't take the ownership of
+// |prop|, so caller must release it by XFree().
+// Returns true if EDID property is successfully obtained. Otherwise returns
+// false and does not touch |prop| and |nitems|.
+BASE_EXPORT bool GetEDIDProperty(XID output,
+                                 unsigned long* nitems,
+                                 unsigned char** prop);
+
+// Gets the EDID data from |output| and generates the display id through
+// |GetDisplayIdFromEDID|.
+BASE_EXPORT bool GetDisplayId(XID output, size_t index,
+                              int64* display_id_out);
+
+// Generates the display id for the pair of |prop| with |nitems| length and
+// |index|, and store in |display_id_out|. Returns true if the display id is
+// successfully generated, or false otherwise.
+BASE_EXPORT bool GetDisplayIdFromEDID(const unsigned char* prop,
+                                      unsigned long nitems,
+                                      size_t index,
+                                      int64* display_id_out);
+
+// Parses |prop| as EDID data and stores extracted data into |manufacturer_id|
+// and |human_readable_name| and returns true. NULL can be passed for unwanted
+// output parameters. Some devices (especially internal displays) may not have
+// the field for |human_readable_name|, and it will return true in that case.
+BASE_EXPORT bool ParseOutputDeviceData(const unsigned char* prop,
+                                       unsigned long nitems,
+                                       uint16* manufacturer_id,
+                                       std::string* human_readable_name);
+
+}  // namespace base
+
+#endif  // BASE_X11_EDID_PARSER_X11_H_