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diff --git a/dom/media/webaudio/blink/FFTConvolver.cpp b/dom/media/webaudio/blink/FFTConvolver.cpp
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+++ b/dom/media/webaudio/blink/FFTConvolver.cpp
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+/*
+ * Copyright (C) 2010 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "FFTConvolver.h"
+#include "mozilla/PodOperations.h"
+
+using namespace mozilla;
+
+namespace WebCore {
+
+FFTConvolver::FFTConvolver(size_t fftSize, size_t renderPhase)
+    : m_frame(fftSize), m_readWriteIndex(renderPhase % (fftSize / 2)) {
+  MOZ_ASSERT(fftSize >= 2 * WEBAUDIO_BLOCK_SIZE);
+  m_inputBuffer.SetLength(fftSize);
+  PodZero(m_inputBuffer.Elements(), fftSize);
+  m_outputBuffer.SetLength(fftSize);
+  PodZero(m_outputBuffer.Elements(), fftSize);
+  m_lastOverlapBuffer.SetLength(fftSize / 2);
+  PodZero(m_lastOverlapBuffer.Elements(), fftSize / 2);
+}
+
+size_t FFTConvolver::sizeOfExcludingThis(
+    mozilla::MallocSizeOf aMallocSizeOf) const {
+  size_t amount = 0;
+  amount += m_frame.SizeOfExcludingThis(aMallocSizeOf);
+  amount += m_inputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  amount += m_outputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  amount += m_lastOverlapBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  return amount;
+}
+
+size_t FFTConvolver::sizeOfIncludingThis(
+    mozilla::MallocSizeOf aMallocSizeOf) const {
+  return aMallocSizeOf(this) + sizeOfExcludingThis(aMallocSizeOf);
+}
+
+const float* FFTConvolver::process(FFTBlock* fftKernel, const float* sourceP) {
+  size_t halfSize = fftSize() / 2;
+
+  // WEBAUDIO_BLOCK_SIZE must be an exact multiple of halfSize,
+  // halfSize must be a multiple of WEBAUDIO_BLOCK_SIZE
+  // and > WEBAUDIO_BLOCK_SIZE.
+  MOZ_ASSERT(halfSize % WEBAUDIO_BLOCK_SIZE == 0 &&
+             WEBAUDIO_BLOCK_SIZE <= halfSize);
+
+  // Copy samples to input buffer (note contraint above!)
+  float* inputP = m_inputBuffer.Elements();
+
+  MOZ_ASSERT(sourceP && inputP &&
+             m_readWriteIndex + WEBAUDIO_BLOCK_SIZE <= m_inputBuffer.Length());
+
+  memcpy(inputP + m_readWriteIndex, sourceP,
+         sizeof(float) * WEBAUDIO_BLOCK_SIZE);
+
+  float* outputP = m_outputBuffer.Elements();
+  m_readWriteIndex += WEBAUDIO_BLOCK_SIZE;
+
+  // Check if it's time to perform the next FFT
+  if (m_readWriteIndex == halfSize) {
+    // The input buffer is now filled (get frequency-domain version)
+    m_frame.PerformFFT(m_inputBuffer.Elements());
+    m_frame.Multiply(*fftKernel);
+    m_frame.GetInverseWithoutScaling(m_outputBuffer.Elements());
+
+    // Overlap-add 1st half from previous time
+    AudioBufferAddWithScale(m_lastOverlapBuffer.Elements(), 1.0f,
+                            m_outputBuffer.Elements(), halfSize);
+
+    // Finally, save 2nd half of result
+    MOZ_ASSERT(m_outputBuffer.Length() == 2 * halfSize &&
+               m_lastOverlapBuffer.Length() == halfSize);
+
+    memcpy(m_lastOverlapBuffer.Elements(), m_outputBuffer.Elements() + halfSize,
+           sizeof(float) * halfSize);
+
+    // Reset index back to start for next time
+    m_readWriteIndex = 0;
+  }
+
+  return outputP + m_readWriteIndex;
+}
+
+void FFTConvolver::reset() {
+  PodZero(m_lastOverlapBuffer.Elements(), m_lastOverlapBuffer.Length());
+  m_readWriteIndex = 0;
+}
+
+size_t FFTConvolver::latencyFrames() const {
+  return std::max<size_t>(fftSize() / 2, WEBAUDIO_BLOCK_SIZE) -
+         WEBAUDIO_BLOCK_SIZE;
+}
+
+}  // namespace WebCore