disable web audio by default on android and add switches to enable it


BUG=
TEST=


Review URL: https://chromiumcodereview.appspot.com/10810034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148516 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index edb3fb0..7fd47682 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -428,8 +428,13 @@
       !command_line.HasSwitch(switches::kDisableLocalStorage);
   prefs.databases_enabled =
       !command_line.HasSwitch(switches::kDisableDatabases);
+#if defined(OS_ANDROID)
+  prefs.webaudio_enabled =
+      command_line.HasSwitch(switches::kEnableWebAudio);
+#else
   prefs.webaudio_enabled =
       !command_line.HasSwitch(switches::kDisableWebAudio);
+#endif
 
   prefs.experimental_webgl_enabled =
       GpuProcessHost::gpu_enabled() &&