Output device enumeration for Alsa, plus unit test.

media/media.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,
     # Override to dynamically link the cras (ChromeOS audio) library.
     'use_cras%': 0,
     # Option e.g. for Linux distributions to link pulseaudio directly
@@ skipping 1021 matching lines @@
         }],
         ['media_use_ffmpeg==1', {
           'dependencies': [
             '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
           ],
         }, {  # media_use_ffmpeg== 0
           'sources!': [
             'base/media_file_checker_unittest.cc',
           ],
         }],
+        ['use_alsa==1', {
+          'defines': [
+            'USE_ALSA',
+          ],
+        }],
         ['use_pulseaudio==1', {
           'defines': [
             'USE_PULSEAUDIO',
           ],
         }],
         ['os_posix==1 and OS!="mac" and OS!="ios"', {
           'conditions': [
             ['linux_use_tcmalloc==1', {
               'dependencies': [
                 '../base/allocator/allocator.gyp:allocator',
@@ skipping 535 matching lines @@
                   ],
                 }],
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }