Add counters for all of the WebAudio nodes and important methods.

LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html

Index: LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html
diff --git a/LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html b/LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html
index 58a528f96168d750d3fd58475f16c91745762aff..0e9c752a344ee8a47083518ac2ecf314981ab77b 100644
--- a/LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html
+++ b/LayoutTests/webaudio/mediaelementaudiosourcenode-wrapper.html
@@ -12,7 +12,7 @@ description("Verifies that for .mediaElement getters, a wrapper that corresponds
 var source;
 function testMediaWrapper(kind) {
     var element = document.createElement(kind);
-    var context = new webkitOfflineAudioContext(1, 1000, 44100);
+    var context = new OfflineAudioContext(1, 1000, 44100);
 
     source = context.createMediaElementSource(element);
     element = context = null;