Make it possible to use OSMesa on Android

ui/gl/gl.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
 
   'targets': [
@@ skipping 64 matching lines @@
         'gl_image_ozone.cc',
         'gl_image_shm.cc',
         'gl_image_shm.h',
         'gl_image_stub.cc',
         'gl_image_stub.h',
         'gl_image_win.cc',
         'gl_image_x11.cc',
         'gl_implementation.cc',
         'gl_implementation.h',
         'gl_implementation_android.cc',
-        'gl_implementation_linux.cc',
-        'gl_implementation_linux.h',
         'gl_implementation_ozone.cc',
         'gl_implementation_mac.cc',
         'gl_implementation_win.cc',
         'gl_implementation_x11.cc',
         'gl_interface.cc',
         'gl_interface.h',
         'gl_osmesa_api_implementation.cc',
         'gl_osmesa_api_implementation.h',
         'gl_share_group.cc',
         'gl_share_group.h',
@@ skipping 89 matching lines @@
             'gl_context_egl.h',
             'gl_surface_egl.cc',
             'gl_surface_egl.h',
             'gl_egl_api_implementation.cc',
             'gl_egl_api_implementation.h',
             '<(gl_binding_output_dir)/gl_bindings_autogen_egl.cc',
             '<(gl_binding_output_dir)/gl_bindings_autogen_egl.h',
           ],
           'include_dirs': [
             '<(DEPTH)/third_party/khronos',
-        ],
+          ],
+        }],
+        ['OS in ("android", "linux", "openbsd", "freebsd")', {
+          'sources': [
+            'gl_implementation_osmesa.cc',
+            'gl_implementation_osmesa.h',
+          ],
         }],
         ['use_x11 == 1', {
           'sources': [
             'gl_context_glx.cc',
             'gl_context_glx.h',
             'gl_glx_api_implementation.cc',
             'gl_glx_api_implementation.h',
             'gl_image_glx.cc',
             'gl_image_glx.h',
             'gl_surface_glx.cc',
@@ skipping 57 matching lines @@
           'sources': [
             'gl_image_egl.cc',
             'gl_image_egl.h',
           ],
           'link_settings': {
             'libraries': [
               '-landroid',
             ],
           },
           'sources!': [
-            'gl_context_osmesa.cc',
             'system_monitor_posix.cc',
           ],
           'defines': [
             'GL_GLEXT_PROTOTYPES',
             'EGL_EGLEXT_PROTOTYPES',
           ],
         }],
         ['OS!="android"', {
           'sources/': [ ['exclude', '^android/'] ],
         }],
@@ skipping 50 matching lines @@
           ],
           'variables': {
             'jni_gen_package': 'ui/gl',
           },
           'includes': [ '../../build/jni_generator.gypi' ],
         },
       ],
     }],
   ],
 }