Make AudioContext work in iOS 7.

Make AudioContext work in iOS 7.

BUG=
R=sra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=28877

[Emily Fortuna, 2013-10-18 20:09:29]

https://codereview.chromium.org/29583004/diff/1/sdk/lib/html/dart2js/html_dar...
File sdk/lib/html/dart2js/html_dart2js.dart (right):

https://codereview.chromium.org/29583004/diff/1/sdk/lib/html/dart2js/html_dar...
sdk/lib/html/dart2js/html_dart2js.dart:29050: +   * the set, otherwise `false`.
spurious change (changes in master, too)

[sra1, 2013-10-18 20:13:24]

https://codereview.chromium.org/29583004/diff/1/sdk/lib/web_audio/dartium/web...
File sdk/lib/web_audio/dartium/web_audio_dartium.dart (right):

https://codereview.chromium.org/29583004/diff/1/sdk/lib/web_audio/dartium/web...
sdk/lib/web_audio/dartium/web_audio_dartium.dart:267: class AudioContext extends
EventTarget native "AudioContext,webkitAudioContext" {
Should not affect dartium

https://codereview.chromium.org/29583004/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_AudioContext.darttemplate (right):

https://codereview.chromium.org/29583004/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_AudioContext.darttemplate:7:
$(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS native
"AudioContext,webkitAudioContext" {
Not here.

change the table in generator.py
_dart2js_dom_custom_native_specs = monitored.Dict(

[Emily Fortuna, 2013-10-18 20:22:19]

whoops. ptal.

[sra1, 2013-10-18 20:34:54]

lgtm

[Emily Fortuna, 2013-10-18 20:37:15]

Committed patchset #5 manually as r28877 (presubmit successful).