Reduce dynamicscompressor threshold.

This allows the test to pass on Windows, but still detects that
pre-emphasis is off.

BUG=349523

Review URL: https://codereview.chromium.org/314743002

git-svn-id: svn://svn.chromium.org/blink/trunk@175536 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -832,7 +832,6 @@ crbug.com/309197 [ Win Debug ] webaudio/oscillator-custom.html [ Skip ]
 crbug.com/309197 [ Win Debug ] webaudio/oscillator-sine.html [ Skip ]
 crbug.com/309197 [ Win Debug ] webaudio/oscillator-square.html [ Skip ]
 
-crbug.com/349523 [ Win ] webaudio/dynamicscompressor-simple.html [ Failure ]
 crbug.com/349523 [ Win ] webaudio/realtimeanalyser-fft-scaling.html [ Failure ]
 crbug.com/352464 http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-subframe-location-change.html [ Pass Failure Missing ]
 crbug.com/372425 http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-subframe.html [ Pass Failure Timeout ]

third_party/WebKit/LayoutTests/webaudio/dynamicscompressor-simple.html

@@ -18,8 +18,8 @@
       var renderedData;
       // This threshold experimentally determined. It depends on the the gain value of the gain node
       // below and the dynamics compressor.  When the DynamicsCompressor had the pre-emphasis
-      // filters, the peak value is about 0.21.  Without it, the peak is 0.85.
-      var peakThreshold = 0.85;
+      // filters, the peak value is about 0.21.  Without it, the peak is about 0.84.
+      var peakThreshold = 0.83;
 
       function checkResult(event) {
         var renderedBuffer = event.renderedBuffer;