Set channelCount and maxChannelCount correctly for OfflineAudioContext.

third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html

Index: third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html
diff --git a/third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html b/third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html
index 3e3aa27fdf51690a38f4bf9e364bde1a650e5cd5..8f0332fbb012756f203f88170d714adac5737af2 100644
--- a/third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html
+++ b/third_party/WebKit/LayoutTests/webaudio/offlineaudiocontext-constructor.html
@@ -34,7 +34,13 @@ shouldBeEqualToNumber("context.length", 512);
 shouldNotThrow("context = new OfflineAudioContext(2, 512, 96000)");
 // Make sure we throw exceptions for non-finite sample rates.
 shouldThrow("context = new OfflineAudioContext(1, 0, NaN)");
-shouldThrow("context = new OfflineAudioContext(1, 0, Infinite)");
+shouldThrow("context = new OfflineAudioContext(1, 0, Infinity)");
+// Verify channel counts and other destination attributes are set correctly.
+shouldNotThrow("context = new OfflineAudioContext(7, 512, 48000)");
+shouldBeEqualToNumber("context.destination.channelCount", 7);
+shouldBeEqualToNumber("context.destination.maxChannelCount", 7);
+shouldBeEqualToString("context.destination.channelCountMode", "explicit");
+shouldBeEqualToString("context.destination.channelInterpretation", "speakers");
 </script>
 </body>
 </html>