Implement two new policies to control muting the audio I/O.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 687d4b12ef93bb349667c5ae3bb084302efe6e6b..769fa2ca5abf3f3e4dedcd45a570299244cd1daa 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1768,6 +1768,14 @@ const char kSyncSpareBootstrapToken[] = "sync.spare_bootstrap_token";
 // storage for the user.
 const char kExternalStorageDisabled[] = "hardware.external_storage_disabled";
 
+// A pref holding the value of the policy used to disable playing audio on
+// ChromeOS devices.
+const char kAudioOutputEnabled[] = "hardware.audio_output_enabled";
+
+// A pref holding the value of the policy used to disable capturing audio on
+// ChromeOS devices.
+const char kAudioCaptureEnabled[] = "hardware.audio_capture_enabled";
+
 // A dictionary that maps usernames to wallpaper properties.
 const char kUsersWallpaperInfo[] = "user_wallpaper_info";
 #endif