Implement Automations for PannerNode and AutioListener

third_party/WebKit/Source/platform/audio/HRTFPanner.cpp

Index: third_party/WebKit/Source/platform/audio/HRTFPanner.cpp
diff --git a/third_party/WebKit/Source/platform/audio/HRTFPanner.cpp b/third_party/WebKit/Source/platform/audio/HRTFPanner.cpp
index e352f4594521680ae4d8d0fe8ced00ed4ce448df..bed5654772da8ebc306510e3cf9b29a6d754d678 100644
--- a/third_party/WebKit/Source/platform/audio/HRTFPanner.cpp
+++ b/third_party/WebKit/Source/platform/audio/HRTFPanner.cpp
@@ -292,6 +292,19 @@ void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* in
     }
 }
 
+void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+{
+    // Sample-accurate (a-rate) HRTF panner is not implemented, just k-rate.  Just grab the current
+    // azimuth/elevation and use that.
+    //
+    // We are assuming that the inherent smoothing in the HRTF processing is good enough, and we
+    // don't want to increase the complexity of the HRTF panner by 15-20 times.  (We need to cmopute
+    // one output sample for each possibly different impulse response.  That N^2.  Previously, we
+    // used an FFT to do them all at once for a complexity of N/log2(N).  Hence, N/log2(N) times
+    // more complex.)
+    pan(desiredAzimuth[0], elevation[0], inputBus, outputBus, framesToProcess);
+}
+
 double HRTFPanner::tailTime() const
 {
     // Because HRTFPanner is implemented with a DelayKernel and a FFTConvolver, the tailTime of the HRTFPanner