gl_context_glx: add workaround to create default context

ui/gl/gl_switches.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_GL_GL_SWITCHES_H_
 #define UI_GL_GL_SWITCHES_H_
 
 // Defines all the command-line switches used by ui/gl.
 
 #include "ui/gl/gl_export.h"
@@ skipping 12 matching lines @@
 GL_EXPORT extern const char kANGLEImplementationDefaultName[];
 GL_EXPORT extern const char kANGLEImplementationD3D9Name[];
 GL_EXPORT extern const char kANGLEImplementationD3D11Name[];
 GL_EXPORT extern const char kANGLEImplementationOpenGLName[];
 GL_EXPORT extern const char kANGLEImplementationOpenGLESName[];
 
 }  // namespace gl
 
 namespace switches {
 
+GL_EXPORT extern const char kCreateDefaultGLContext[];
 GL_EXPORT extern const char kDisableD3D11[];
 GL_EXPORT extern const char kDisableES3GLContext[];
 GL_EXPORT extern const char kDisableGpuVsync[];
 GL_EXPORT extern const char kEnableGPUServiceLogging[];
 GL_EXPORT extern const char kEnableGPUServiceTracing[];
 GL_EXPORT extern const char kGpuNoContextLost[];
 GL_EXPORT extern const char kDisableDirectComposition[];
 
 GL_EXPORT extern const char kSupportsDualGpus[];
 
@@ skipping 10 matching lines @@
 // These flags are used by the test harness code, not passed in by users.
 GL_EXPORT extern const char kDisableGLDrawingForTests[];
 GL_EXPORT extern const char kOverrideUseGLWithOSMesaForTests[];
 
 GL_EXPORT extern const char* kGLSwitchesCopiedFromGpuProcessHost[];
 GL_EXPORT extern const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches;
 
 }  // namespace switches
 
 #endif  // UI_GL_GL_SWITCHES_H_