Linux: Add xcb FD to glib event loop

ui/gfx/x/x11_types.cc

Index: ui/gfx/x/x11_types.cc
diff --git a/ui/gfx/x/x11_types.cc b/ui/gfx/x/x11_types.cc
index 7540f8ae2887cbcdcebf09982790a8a8ba797314..646d678079465782373604fb51825e8a4e696d8d 100644
--- a/ui/gfx/x/x11_types.cc
+++ b/ui/gfx/x/x11_types.cc
@@ -5,6 +5,8 @@
 #include "ui/gfx/x/x11_types.h"
 
 #include <X11/Xlib.h>
+#include <xcb/xcb.h>
+#include <X11/Xlib-xcb.h>
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
@@ -26,7 +28,14 @@ XDisplay* OpenNewXDisplay() {
 #else
   std::string display_str = base::CommandLine::ForCurrentProcess()->
                             GetSwitchValueASCII(switches::kX11Display);
-  return XOpenDisplay(display_str.empty() ? NULL : display_str.c_str());
+  // TODO(thomasanderson): Do not upload this.  Remove once builders pass.
+  xcb_connection_t* connection =
+      xcb_connect(display_str.empty() ? NULL : display_str.c_str(), nullptr);
+  (void)connection;
+  XDisplay* display =
+      XOpenDisplay(display_str.empty() ? NULL : display_str.c_str());
+  (void)XGetXCBConnection(display);
+  return display;
 #endif
 }
 
@@ -173,4 +182,3 @@ void PutARGBImage(XDisplay* display,
 }
 
 }  // namespace gfx
-