Implement tail processing for AudioNodes

third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html

Index: third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html
diff --git a/third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html b/third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html
index 34f5cd20644a49647b77974560e338796c077219..9c5ae95cf6a9037efbd61c13c34ede6313695160 100644
--- a/third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html
+++ b/third_party/WebKit/LayoutTests/webaudio/DynamicsCompressor/dynamicscompressor-clear-internal-state.html
@@ -17,8 +17,10 @@
       let source;
       let compressor;
 
-      let sampleRate = 44100;
-      let testDurationSamples = 44100;
+      // Use a low sample rate to reduce complexity because we need to run for
+      // quite a few seconds to get the reduction to converge.
+      let sampleRate = 8192;
+      let testDurationSamples = 10 * 8192;
 
       audit.define(
           {
@@ -46,8 +48,12 @@
 
             // Render it!
             context.startRendering().then(() => {
-              // Check that the reduction value is 0.0.
-              should(compressor.reduction, 'compressor.reduction').beEqualTo(0);
+              // Check that the reduction value sufficiently close to 0.
+              // Threshold experimentally determined.
+              should(
+                  Math.abs(compressor.reduction),
+                  'Math.abs(compressor.reduction)')
+                  .beLessThanOrEqualTo(4.8223e-2);
               task.done();
             });
           });