Add support for WaveShaperNode.oversample

Source/modules/webaudio/WaveShaperProcessor.cpp

Index: Source/modules/webaudio/WaveShaperProcessor.cpp
diff --git a/Source/modules/webaudio/WaveShaperProcessor.cpp b/Source/modules/webaudio/WaveShaperProcessor.cpp
index c560de5bb9efc3d13ae6dacaf29b21109838a968..f4b5efa728f0bab4f4312c95b3304e0758d975bb 100644
--- a/Source/modules/webaudio/WaveShaperProcessor.cpp
+++ b/Source/modules/webaudio/WaveShaperProcessor.cpp
@@ -31,9 +31,10 @@
 #include "modules/webaudio/WaveShaperDSPKernel.h"
 
 namespace WebCore {
-    
+
 WaveShaperProcessor::WaveShaperProcessor(float sampleRate, size_t numberOfChannels)
     : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
+    , m_oversample(OverSampleNone)
 {
 }
 
@@ -56,6 +57,21 @@ void WaveShaperProcessor::setCurve(Float32Array* curve)
     m_curve = curve;
 }
 
+void WaveShaperProcessor::setOversample(OverSampleType oversample)
+{
+    // This synchronizes with process().
+    MutexLocker processLocker(m_processLock);
+
+    m_oversample = oversample;
+
+    if (oversample != OverSampleNone) {
+        for (unsigned i = 0; i < m_kernels.size(); ++i) {
+            WaveShaperDSPKernel* kernel = static_cast<WaveShaperDSPKernel*>(m_kernels[i].get());
+            kernel->lazyInitializeOversampling();
+        }
+    }
+}
+
 void WaveShaperProcessor::process(const AudioBus* source, AudioBus* destination, size_t framesToProcess)
 {
     if (!isInitialized()) {