Implement IIRFilter node for WebAudio.

third_party/WebKit/Source/modules/webaudio/IIRFilterNode.idl

Index: third_party/WebKit/Source/modules/webaudio/IIRFilterNode.idl
diff --git a/third_party/WebKit/Source/modules/webaudio/IIRFilterNode.idl b/third_party/WebKit/Source/modules/webaudio/IIRFilterNode.idl
new file mode 100644
index 0000000000000000000000000000000000000000..d84eb299f6134a3541f006b17a398115e741b900
--- /dev/null
+++ b/third_party/WebKit/Source/modules/webaudio/IIRFilterNode.idl
@@ -0,0 +1,12 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+[
+    NoInterfaceObject,
+    Conditional=WEB_AUDIO
+] interface IIRFilterNode : AudioNode {
+    [RaisesException] void getFrequencyResponse(Float32Array frequencyHz,
+                                                Float32Array magResponse,
+                                                Float32Array phaseResponse);
+};