x11: Move XInput2 availability information out of the message pump.

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 33 matching lines @@
 
 namespace ui {
 
 // These functions use the default display and this /must/ be called from
 // the UI thread. Thus, they don't support multiple displays.
 
 // These functions cache their results ---------------------------------
 
 // Check if there's an open connection to an X server.
 UI_EXPORT bool XDisplayExists();
-// Return an X11 connection for the current, primary display.
+
+// Returns true if the system supports XINPUT2.
+UI_EXPORT bool IsXInput2Available();
 
 // X shared memory comes in three flavors:
 // 1) No SHM support,
 // 2) SHM putimage,
 // 3) SHM pixmaps + putimage.
 enum SharedMemorySupport {
   SHARED_MEMORY_NONE,
   SHARED_MEMORY_PUTIMAGE,
   SHARED_MEMORY_PIXMAP
 };
@@ skipping 312 matching lines @@
  private:
   ::Cursor cursor_;
   XDisplay* display_;
 
   DISALLOW_COPY_AND_ASSIGN(XScopedCursor);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_