chrome.audio API: treat mute as system wide property

extensions/test/data/api_test/audio/input_mute_change/background.js

Index: extensions/test/data/api_test/audio/input_mute_change/background.js
diff --git a/extensions/test/data/api_test/audio/input_mute_change/background.js b/extensions/test/data/api_test/audio/input_mute_change/background.js
index 39fbc86adec937ed62f4c0d811e3693a29e7ed50..3c4437e5076e8c395093965004fb37efbfc3db41 100644
--- a/extensions/test/data/api_test/audio/input_mute_change/background.js
+++ b/extensions/test/data/api_test/audio/input_mute_change/background.js
@@ -5,10 +5,10 @@
 chrome.test.runTests([
   function waitForMuteChangedEventTests() {
     chrome.test.listenOnce(
-        chrome.audio.OnMuteChanged,
-        function(isInput, isMuted) {
-          chrome.test.assertTrue(isInput);
-          chrome.test.assertTrue(isMuted);
+        chrome.audio.onMuteChanged,
+        function(evt) {
+          chrome.test.assertEq('INPUT', evt.streamType);
+          chrome.test.assertTrue(evt.value);
         });
   }
 ]);