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diff --git a/dom/media/webaudio/blink/ZeroPole.cpp b/dom/media/webaudio/blink/ZeroPole.cpp
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+++ b/dom/media/webaudio/blink/ZeroPole.cpp
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+/*
+ * Copyright (C) 2011 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 "ZeroPole.h"
+
+#include "DenormalDisabler.h"
+
+#include <cmath>
+#include <float.h>
+
+namespace WebCore {
+
+void ZeroPole::process(const float* source, float* destination,
+                       int framesToProcess) {
+  float zero = m_zero;
+  float pole = m_pole;
+
+  // Gain compensation to make 0dB @ 0Hz
+  const float k1 = 1 / (1 - zero);
+  const float k2 = 1 - pole;
+
+  // Member variables to locals.
+  float lastX = m_lastX;
+  float lastY = m_lastY;
+
+  for (int i = 0; i < framesToProcess; ++i) {
+    float input = source[i];
+
+    // Zero
+    float output1 = k1 * (input - zero * lastX);
+    lastX = input;
+
+    // Pole
+    float output2 = k2 * output1 + pole * lastY;
+    lastY = output2;
+
+    destination[i] = output2;
+  }
+
+// Locals to member variables. Flush denormals here so we don't
+// slow down the inner loop above.
+#ifndef HAVE_DENORMAL
+  if (lastX == 0.0f && lastY != 0.0f && fabsf(lastY) < FLT_MIN) {
+    // Flush future values to zero (until there is new input).
+    lastY = 0.0;
+
+    // Flush calculated values.
+    for (int i = framesToProcess; i-- && fabsf(destination[i]) < FLT_MIN;) {
+      destination[i] = 0.0f;
+    }
+  }
+#endif
+
+  m_lastX = lastX;
+  m_lastY = lastY;
+}
+
+}  // namespace WebCore