Added constructor for AudioContext for dartc and frog

client/dom/generated/src/frog/AudioContext.dart

 
 class AudioContext native "*AudioContext" {
+  AudioContext() native;

[sra1, 2011/12/08 06:19:16]

It is slightly strange to have a plain constructor for a hidden type.  I looked
at the unified browser info and AudioContext is 'hidden' on *all* our target
browsers.

The WebKit IDL for DOMWindow contains
        attribute [JSCCustomGetter,Conditional=WEB_AUDIO,EnabledAtRuntime]
AudioContextConstructor webkitAudioContext; // Usable with new operator

which will appear in the JavaScript global scope.

So the constructor should be:

factory AudioContext() native @'return new webkitAudioContext();';

The dartc version also needs to call the right constructor.

[Jennifer Messerly, 2011/12/08 06:31:21]

If "webkitAudioContext" is the constructor, why not just make that the native
type name?
It's nice to make things non-hidden when possible.

I tried this out, worked great:
$ webkitAudioContext
function AudioContext() { [native code] }
$ webkitAudioContext.prototype.hello = function(){console.log("hello");}
$ new webkitAudioContext().hello
function (){console.log("hello");}
$ new webkitAudioContext().hello()
hello
$ new webkitAudioContext() instanceof webkitAudioContext
true

+
 
   num currentTime;
 
   AudioDestinationNode destination;
 
   AudioListener listener;
 
   num sampleRate;
 
   RealtimeAnalyserNode createAnalyser() native;
@@ skipping 27 matching lines @@
   WaveShaperNode createWaveShaper() native;
 
   void decodeAudioData(ArrayBuffer audioData, AudioBufferCallback successCallback, [AudioBufferCallback errorCallback = null]) native;
 
   void startRendering() native;
 
   var dartObjectLocalStorage;
 
   String get typeName() native;
 }