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 246 matching lines @@
             'gl_surface_nsview.h',
           ],
         }],
         ['OS=="android"', {
           'dependencies': [
             'gl_jni_headers',
           ],
           'sources': [
             'gl_image_egl.cc',
             'gl_image_egl.h',
+            'gl_implementation_linux.cc',
+            'gl_implementation_linux.h',

[Peter Beverloo, 2013/10/03 19:46:42]

I've tried a ton of things (regular inclusions like this, sources/ include
expressions) to get gl_implementation_linux.cc to be included in Android's
target, but it doesn't want to work.

Does anyone know the gyp structure in ui/gl/ who can understand why a normal
override of the OS-specific regexp (filename_rules.gypi:32) doesn't work here? 
I should be able to use:

'sources/': [
  ['include', 'gl_implementation_linux\\.cc$'],
],

but that doesn't work (tried with a full path, no escaping, regexp for (cc|h),
and so on)...

[piman, 2013/10/03 19:54:18]

Not sure... Feel free to rename this (though I can't come up with a good name),
and add it explicitly on linux/android.

           ],
           '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' ],
         },
       ],
     }],
   ],
 }