add a use_alsa gyp setting

media/media.gyp

Index: media/media.gyp
diff --git a/media/media.gyp b/media/media.gyp
index 7485411b955dbe4c00cd55554c64c9d98e7e9dc2..52b9abd28f6d0305c115cbe07e8e9cf655fce272 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -25,6 +25,12 @@
       }, {
         'screen_capture_supported%': 0,
       }],
+      # ALSA usage.
+      ['OS=="linux" or OS=="freebsd" or OS=="solaris"', {
+        'use_alsa%': 1,
+      }, {
+        'use_alsa%': 0,
+      }],
     ],
   },
   'targets': [
@@ -550,20 +556,15 @@
             'webm/chromeos/webm_encoder.h',
           ],
         }],
-        ['OS=="linux" or OS=="freebsd" or OS=="solaris"', {
+        ['use_alsa==1', {

[DaleCurtis, 2013/02/21 20:57:29]

Long term, ideally, I'd like to get rid of all the use_alsa, use_cras, use_pulse
flags and just dlsym the libraries at runtime instead.

OOC what output driver are you using if not Alsa? Pulse, CrAS, something else?

           'link_settings': {
             'libraries': [
               '-lasound',
             ],
           },
-        }],
-        ['OS=="openbsd"', {
+        }, { # use_alsa==0
           'sources/': [ ['exclude', '/alsa_' ],
-                        ['exclude', '/audio_manager_linux' ] ],
-          'link_settings': {
-            'libraries': [
-            ],
-          },
+                      ['exclude', '/audio_manager_linux' ] ],
         }],
         ['OS!="openbsd"', {
           'sources!': [
@@ -943,6 +944,12 @@
             }],
           ],
         }],
+        ['use_alsa==0', {
+          'sources!': [
+            'audio/linux/alsa_output_unittest.cc',
+            'audio/audio_low_latency_input_output_unittest.cc',
+          ],
+        }],
         [ 'target_arch=="ia32" or target_arch=="x64"', {
           'sources': [
             'base/simd/convert_rgb_to_yuv_unittest.cc',