Implement IIRFilter node for WebAudio.

third_party/WebKit/Source/modules/webaudio/AudioNode.cpp

Index: third_party/WebKit/Source/modules/webaudio/AudioNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioNode.cpp b/third_party/WebKit/Source/modules/webaudio/AudioNode.cpp
index 60f3edcd1461f3db5fce6cc4ccf95bab0f528278..2ee934de8990b7c8667c5dc021991ca24d6271c3 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioNode.cpp
@@ -412,14 +412,15 @@ void AudioHandler::disableOutputsIfNecessary()
         // But internally our outputs should be disabled from the inputs they're connected to.
         // disable() can recursively deref connections (and call disable()) down a whole chain of connected nodes.
 
-        // TODO(rtoy,hongchan): we special case the convolver, delay, and biquad since they have a
-        // significant tail-time and shouldn't be disconnected simply because they no longer have
-        // any input connections. This needs to be handled more generally where AudioNodes have a
-        // tailTime attribute. Then the AudioNode only needs to remain "active" for tailTime seconds
-        // after there are no longer any active connections.
+        // TODO(rtoy,hongchan): we special case the convolver, delay, biquad, and IIR since they

[hongchan, 2015/10/09 18:10:00]

'we special case...' - perhaps typo? It's not from this CL, but we can fix this
while we're at this.

[Raymond Toy, 2015/10/09 19:41:15]

Done.  (I think.)

+        // have a significant tail-time and shouldn't be disconnected simply because they no longer
+        // have any input connections. This needs to be handled more generally where AudioNodes have
+        // a tailTime attribute. Then the AudioNode only needs to remain "active" for tailTime
+        // seconds after there are no longer any active connections.
         if (nodeType() != NodeTypeConvolver
             && nodeType() != NodeTypeDelay
-            && nodeType() != NodeTypeBiquadFilter) {
+            && nodeType() != NodeTypeBiquadFilter
+            && nodeType() != NodeTypeIIRFilter) {
             m_isDisabled = true;
             clearInternalStateWhenDisabled();
             for (auto& output : m_outputs)