Don't read past the end of the impulseResponse array

Source/core/platform/audio/ReverbConvolverStage.cpp

Index: Source/core/platform/audio/ReverbConvolverStage.cpp
diff --git a/Source/core/platform/audio/ReverbConvolverStage.cpp b/Source/core/platform/audio/ReverbConvolverStage.cpp
index e4c9954910c0639082bcbff51715c5b983d38f51..51fe898315281507a1660bdde65e1f74b9259b19 100644
--- a/Source/core/platform/audio/ReverbConvolverStage.cpp
+++ b/Source/core/platform/audio/ReverbConvolverStage.cpp
@@ -58,8 +58,11 @@ ReverbConvolverStage::ReverbConvolverStage(const float* impulseResponse, size_t,
         m_fftKernel->doPaddedFFT(impulseResponse + stageOffset, stageLength);
         m_fftConvolver = adoptPtr(new FFTConvolver(fftSize));
     } else {
+        ASSERT(!stageOffset);
+        ASSERT(stageLength <= fftSize / 2);
+
         m_directKernel = adoptPtr(new AudioFloatArray(fftSize / 2));
-        m_directKernel->copyToRange(impulseResponse + stageOffset, 0, fftSize / 2);
+        m_directKernel->copyToRange(impulseResponse, 0, stageLength);
         m_directConvolver = adoptPtr(new DirectConvolver(renderSliceSize));
     }
     m_temporaryBuffer.allocate(renderSliceSize);