Expose attack, release as DynamicsCompressorNode's attributes.

Expose attack, release as DynamicsCompressorNode's attributes.
https://bugs.webkit.org/show_bug.cgi?id=81221

Patch by Gao Chun <chun.gao@intel.com> on 2012-03-15
Reviewed by Chris Rogers.

Source/WebCore:

Test: webaudio/dynamicscompressor-basic.html

* platform/audio/DynamicsCompressor.h:
(DynamicsCompressor):
* webaudio/DynamicsCompressorNode.cpp:
(WebCore::DynamicsCompressorNode::DynamicsCompressorNode):
(WebCore::DynamicsCompressorNode::process):
* webaudio/DynamicsCompressorNode.h:
(WebCore::DynamicsCompressorNode::attack):
(WebCore::DynamicsCompressorNode::release):
(DynamicsCompressorNode):
* webaudio/DynamicsCompressorNode.idl:

LayoutTests:

* webaudio/dynamicscompressor-basic-expected.txt:
* webaudio/dynamicscompressor-basic.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@110951 268f45cc-cd09-0410-ab3c-d52691b4dbfc