Use persistent ID/names for displays.

ui/base/x/x11_util.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 UI_BASE_X_X11_UTIL_H_
 #define UI_BASE_X_X11_UTIL_H_
 
 // This file declares utility functions for X11 (Linux only).
 //
 // These functions do not require the Xlib headers to be included (which is why
@@ skipping 218 matching lines @@
                             XID pixmap, void* pixmap_gc,
                             const uint8* data,
                             int data_width, int data_height,
                             int src_x, int src_y,
                             int dst_x, int dst_y,
                             int copy_width, int copy_height);
 
 void FreePicture(Display* display, XID picture);
 void FreePixmap(Display* display, XID pixmap);
 
+// Gets the list of the output displaying device handles via XRandR, and sets to
+// |outputs|.  Returns false if it fails to get the list and |outputs| is
+// cleared.
+UI_EXPORT bool GetOutputDeviceHandles(std::vector<XID>* outputs);
+
+// Gets some useful data from the specified output device, such like
+// manufacturer's ID, serial#, and human readable name. Returns false if it
+// fails to get those data and doesn't touch manufacturer ID/serial#/name.
+// You can pass NULL to |manufacturer_id|, |serial_number|, and
+// |human_readable_name| then it just ignores them.
+UI_EXPORT bool GetOutputDeviceData(XID output,
+                                   uint16* manufacturer_id,
+                                   uint32* serial_number,
+                                   std::string* human_readable_name);
+
 enum WindowManagerName {
   WM_UNKNOWN,
   WM_BLACKBOX,
   WM_CHROME_OS,
   WM_COMPIZ,
   WM_ENLIGHTENMENT,
   WM_ICE_WM,
   WM_KWIN,
   WM_METACITY,
   WM_MUTTER,
@@ skipping 43 matching lines @@
 
  private:
   char* string_;
 
   DISALLOW_COPY_AND_ASSIGN(XScopedString);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_