Implement IIRFilter node for WebAudio.

third_party/WebKit/Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 206 matching lines @@
       'webaudio/AudioParam.idl',
       'webaudio/AudioProcessingEvent.idl',
       'webaudio/AudioSourceNode.idl',
       'webaudio/BiquadFilterNode.idl',
       'webaudio/ChannelMergerNode.idl',
       'webaudio/ChannelSplitterNode.idl',
       'webaudio/ConvolverNode.idl',
       'webaudio/DelayNode.idl',
       'webaudio/DynamicsCompressorNode.idl',
       'webaudio/GainNode.idl',
+      'webaudio/IIRFilterNode.idl',
       'webaudio/MediaElementAudioSourceNode.idl',
       'webaudio/MediaStreamAudioDestinationNode.idl',
       'webaudio/MediaStreamAudioSourceNode.idl',
       'webaudio/OfflineAudioCompletionEvent.idl',
       'webaudio/OfflineAudioContext.idl',
       'webaudio/OscillatorNode.idl',
       'webaudio/PannerNode.idl',
       'webaudio/PeriodicWave.idl',
       'webaudio/ScriptProcessorNode.idl',
       'webaudio/StereoPannerNode.idl',
@@ skipping 1315 matching lines @@
       'webaudio/DelayDSPKernel.cpp',
       'webaudio/DelayDSPKernel.h',
       'webaudio/DelayNode.cpp',
       'webaudio/DelayNode.h',
       'webaudio/DelayProcessor.cpp',
       'webaudio/DelayProcessor.h',
       'webaudio/DynamicsCompressorNode.cpp',
       'webaudio/DynamicsCompressorNode.h',
       'webaudio/GainNode.cpp',
       'webaudio/GainNode.h',
+      'webaudio/IIRDSPKernel.h',
+      'webaudio/IIRDSPKernel.cpp',
+      'webaudio/IIRFilterNode.cpp',
+      'webaudio/IIRFilterNode.h',
+      'webaudio/IIRProcessor.h',
+      'webaudio/IIRProcessor.cpp',
       'webaudio/MediaElementAudioSourceNode.cpp',
       'webaudio/MediaElementAudioSourceNode.h',
       'webaudio/MediaStreamAudioDestinationNode.cpp',
       'webaudio/MediaStreamAudioDestinationNode.h',
       'webaudio/MediaStreamAudioSourceNode.cpp',
       'webaudio/MediaStreamAudioSourceNode.h',
       'webaudio/OfflineAudioCompletionEvent.cpp',
       'webaudio/OfflineAudioCompletionEvent.h',
       'webaudio/OfflineAudioContext.cpp',
       'webaudio/OfflineAudioContext.h',
@@ skipping 323 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }