Turn on UIPI for the GPU sandbox.

ui/gfx/gl/gl_implementation.h

Index: ui/gfx/gl/gl_implementation.h
===================================================================
--- ui/gfx/gl/gl_implementation.h	(revision 93936)
+++ ui/gfx/gl/gl_implementation.h	(working copy)
@@ -10,6 +10,7 @@
 
 #include "base/native_library.h"
 #include "build/build_config.h"
+#include "ui/gfx/gl/gl_switches.h"
 
 namespace gfx {
 
@@ -22,12 +23,6 @@
   kGLImplementationMockGL
 };
 
-// The GL implementation names that can be passed to --use-gl.
-extern const char kGLImplementationDesktopName[];
-extern const char kGLImplementationOSMesaName[];
-extern const char kGLImplementationEGLName[];
-extern const char kGLImplementationMockName[];
-
 #if defined(OS_WIN)
 typedef void* (WINAPI *GLGetProcAddressProc)(const char* name);
 #else