Looping AudioBufferSourceNodes stop only if duration is explicitly given.

LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html

Index: LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html
diff --git a/LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html b/LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html
index 1ddb02073c7279d0bea8418fbea25ab9815de685..4011122abaaa38000b43b2b427606adc5007f32c 100644
--- a/LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html
+++ b/LayoutTests/webaudio/audiobuffersource-loop-comprehensive.html
@@ -137,13 +137,13 @@ var tests = [
 
 // Start a loop with a duration longer than the buffer.  The output should be the data from frame 1
 // to 6, and then looping from 3 to 5 until 30 frames have been played.
-{ description: "loop from 3 -> 6 with offset 1 for 31 frames",
+{ description: "loop from 3 -> 6 with offset 1 for 20 frames",
   loopStartFrame: 3,
   loopEndFrame: 6,
   playbackRate: 1,
   offsetFrame: 1,
-  durationFrames: 30,
-  expected: [1, 2, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3] },
+  durationFrames: 20,
+  expected: [1, 2, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 3, 4, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] },
       
 ];