Precision updates in WebAudio.

Precision updates in WebAudio.
https://bugs.webkit.org/show_bug.cgi?id=119739

Patch by Praveen R Jadhav <praveen.j@samsung.com> on 2013-09-05
Reviewed by Philippe Normand.

WebAudio Specification suggests to use 'double' datatypes
for minDecibels, maxDecibels and smoothingTimeConstant in
AnalyserNode.idl and currentTime in AudioContext.idl.
Current WebKit implementation has declared these attributes
as 'float' type.

Spec: https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#AudioContext-section
      https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#AnalyserNode

No new tests, covered by existing tests.

* Modules/webaudio/AnalyserNode.cpp:
(WebCore::AnalyserNode::setMinDecibels):
(WebCore::AnalyserNode::setMaxDecibels):
(WebCore::AnalyserNode::setSmoothingTimeConstant):
* Modules/webaudio/AnalyserNode.h:
(WebCore::AnalyserNode::minDecibels):
(WebCore::AnalyserNode::maxDecibels):
(WebCore::AnalyserNode::smoothingTimeConstant):
* Modules/webaudio/AnalyserNode.idl:
* Modules/webaudio/AudioContext.idl:
* Modules/webaudio/RealtimeAnalyser.h:
(WebCore::RealtimeAnalyser::setMinDecibels):
(WebCore::RealtimeAnalyser::minDecibels):
(WebCore::RealtimeAnalyser::setMaxDecibels):
(WebCore::RealtimeAnalyser::maxDecibels):
(WebCore::RealtimeAnalyser::setSmoothingTimeConstant):
(WebCore::RealtimeAnalyser::smoothingTimeConstant):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@155112 268f45cc-cd09-0410-ab3c-d52691b4dbfc