Add new gpu driver bug workaround DISABLE_TRANSPARENT_VISUALS

ui/gfx/x/x11_switches.cc

Index: ui/gfx/x/x11_switches.cc
diff --git a/ui/gfx/x/x11_switches.cc b/ui/gfx/x/x11_switches.cc
index fd48792a578bf894e66476d58381bacb40cf7adb..931bfb9c7ad142f10df5d9872c5341eca7f17db1 100644
--- a/ui/gfx/x/x11_switches.cc
+++ b/ui/gfx/x/x11_switches.cc
@@ -8,13 +8,6 @@
 namespace switches {
 
 #if !defined(OS_CHROMEOS)
-// When enabled, tries to get a transparent X11 visual so that we can have
-// per-pixel alpha in windows.
-//
-// TODO(erg): Remove this switch once we've stabilized the code
-// path. http://crbug.com/369209
-const char kEnableTransparentVisuals[] = "enable-transparent-visuals";
-
 // Color bit depth of the main window created in the browser process and matches
 // XWindowAttributes.depth.
 const char kWindowDepth[] = "window-depth";