Add constructors for WebAudio nodes

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

Index: third_party/WebKit/Source/modules/webaudio/DynamicsCompressorOptions.idl
diff --git a/third_party/WebKit/Source/modules/webaudio/DynamicsCompressorOptions.idl b/third_party/WebKit/Source/modules/webaudio/DynamicsCompressorOptions.idl
new file mode 100644
index 0000000000000000000000000000000000000000..b19310131343fc2e4d60d0c559c4620a500ce8d0
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+++ b/third_party/WebKit/Source/modules/webaudio/DynamicsCompressorOptions.idl
@@ -0,0 +1,12 @@
+// Copyright 2016 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.
+
+// See https://webaudio.github.io/web-audio-api/#dynamicscompressoroptions
+dictionary DynamicsCompressorOptions : AudioNodeOptions {
+    float attack;
+    float knee;
+    float ratio;
+    float release;
+    float threshold;
+};