ui: Enable virtual contexts for linux

ui/gl/gl_surface_x11.cc

 // 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.
 
 #include "ui/gl/gl_surface.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 301 matching lines @@
   switch (GetGLImplementation()) {
     case kGLImplementationOSMesaGL: {
       scoped_refptr<GLSurface> surface(
           new GLSurfaceOSMesa(OSMesaSurfaceFormatRGBA, size));
       if (!surface->Initialize())
         return NULL;
 
       return surface;
     }
     case kGLImplementationDesktopGL: {
-      scoped_refptr<GLSurface> surface(new PbufferGLSurfaceGLX(size));
+      scoped_refptr<GLSurface> surface(
+          new UnmappedNativeViewGLSurfaceGLX(size));
       if (!surface->Initialize())
         return NULL;
 
       return surface;
     }
     case kGLImplementationEGLGLES2: {
       scoped_refptr<GLSurface> surface(new PbufferGLSurfaceEGL(size));
       if (!surface->Initialize())
         return NULL;
 
       return surface;
     }
     case kGLImplementationMockGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return NULL;
   }
 }
 
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay() {
   return gfx::GetXDisplay();
 }
 
 }  // namespace gfx