Compute tail time from Biquad coefficients

third_party/WebKit/Source/platform/audio/Biquad.h

Index: third_party/WebKit/Source/platform/audio/Biquad.h
diff --git a/third_party/WebKit/Source/platform/audio/Biquad.h b/third_party/WebKit/Source/platform/audio/Biquad.h
index 7a6bde199c65a8e572a4bb79f021ace858f0ef88..9d51ba31d174b6c78a67095d10680e8f4a4abd2f 100644
--- a/third_party/WebKit/Source/platform/audio/Biquad.h
+++ b/third_party/WebKit/Source/platform/audio/Biquad.h
@@ -70,6 +70,13 @@ class PLATFORM_EXPORT Biquad final {
   // Resets filter state
   void Reset();
 
+  // Compute tail frame based on the filter coefficents at index
+  // |coef_index|.  The tail frame is the frame number where the
+  // impulse response of the filter falls below a threshold value.
+  // The maximum allowed frame value is given by |max_frame|.  This
+  // limits how much work is done in computing the frame numer.
+  double TailFrame(int coef_index, double max_frame);
+
   // Filter response at a set of n frequencies. The magnitude and
   // phase response are returned in magResponse and phaseResponse.
   // The phase response is in radians.