Make the gyp files more cross-platform across the Unices

ui/gfx/gl/gl.gyp

 # Copyright (c) 2011 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.
 
 {
   'target_defaults': {
     'sources/': [
       ['exclude', '/(cocoa|gtk|win)/'],
       ['exclude', '_(cocoa|gtk|linux|mac|posix|win|x)\\.(cc|mm?)$'],
       ['exclude', '/(gtk|win|x11)_[^/]*\\.cc$'],
     ],
     'conditions': [
-      ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {'sources/': [
+      ['toolkit_uses_gtk == 1', {'sources/': [
         ['include', '/gtk/'],
         ['include', '_(gtk|linux|posix|skia|x)\\.cc$'],
         ['include', '/(gtk|x11)_[^/]*\\.cc$'],
       ]}],
       ['OS=="mac"', {'sources/': [
         ['include', '/cocoa/'],
         ['include', '_(cocoa|mac|posix)\\.(cc|mm?)$'],
       ]}, { # else: OS != "mac"
         'sources/': [
           ['exclude', '\\.mm?$'],
@@ skipping 92 matching lines @@
             '<(gl_binding_output_dir)/gl_bindings_autogen_wgl.h',
           ],
           'action': [
             'python',
             'generate_bindings.py',
             '<(gl_binding_output_dir)',
           ],
         },
       ],
       'conditions': [
-        ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="win"', {
+        ['OS != "mac"', {
           'sources': [
             'egl_util.cc',
             'egl_util.h',
             'gl_context_egl.cc',
             'gl_context_egl.h',
             'gl_surface_egl.cc',
             'gl_surface_egl.h',
             '<(gl_binding_output_dir)/gl_bindings_autogen_egl.cc',
             '<(gl_binding_output_dir)/gl_bindings_autogen_egl.h',
           ],
           'include_dirs': [
             '<(DEPTH)/third_party/angle/include',
           ],
         }],
-        ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
+        ['use_x11 == 1', {
           'sources': [
             'gl_context_glx.cc',
             'gl_context_glx.h',
             'gl_surface_glx.cc',
             'gl_surface_glx.h',
             '<(gl_binding_output_dir)/gl_bindings_autogen_glx.cc',
             '<(gl_binding_output_dir)/gl_bindings_autogen_glx.h',
           ],
           'all_dependent_settings': {
             'defines': [
@@ skipping 21 matching lines @@
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/OpenGL.framework',
             ],
           },
         }],
       ],
     },
   ],
 }