FileReference: download() html5 improvements

If we allow the download method to be exposed on html5, it should at least do something. This change makes it work minimally even though we can not open a file dialog on all browsers yet. 

Chromes File API is slowly being adopted, so we may be able to support this better in the future.

src/openfl/net/FileReference.hx

@@ -480,6 +480,8 @@ class FileReference extends EventDispatcher
 	@:noCompletion private var __urlLoader:URLLoader;
 	#if (js && html5)
 	@:noCompletion private var __inputControl:InputElement;
+	@:noCompletion private var __pendingDownload:Bool = false;
+	@:noCompletion private var __pendingDefaultFileName:Null<String>;
 	#end
 
 	/**
@@ -853,6 +855,11 @@ class FileReference extends EventDispatcher
 		saveFileDialog.onSelect.add(saveFileDialog_onSelect);
 		saveFileDialog.browse(SAVE, defaultFileName != null ? Path.extension(defaultFileName) : null, defaultFileName);
 		#end
+
+		#if(js && html5)
+		__pendingDownload = true;
+		__pendingDefaultFileName = defaultFileName;
+		#end
 	}
 
 	/**
@@ -1469,7 +1476,6 @@ class FileReference extends EventDispatcher
 
 	@:noCompletion private function urlLoader_download_onComplete(event:Event):Void
 	{
-		#if (desktop && sys)
 		if ((__urlLoader.data is ByteArrayData))
 		{
 			__data = __urlLoader.data;
@@ -1479,7 +1485,8 @@ class FileReference extends EventDispatcher
 			__data = new ByteArray();
 			__data.writeUTFBytes(Std.string(__urlLoader.data));
 		}
-
+
+		#if (desktop && sys)
 		if (__path != null)
 		{
 			File.saveBytes(__path, __data);
@@ -1489,6 +1496,18 @@ class FileReference extends EventDispatcher
 		}
 		#end
 
+		#if(js && html5)
+		#if(lime && !macro)
+		if(__pendingDownload){
+			//Maybe just use an achor element and save the data as a blob with js instead of invoking lime?
+			var saveFileDialog = new FileDialog();
+			saveFileDialog.save(__data, __pendingDefaultFileName != null ? Path.extension(__pendingDefaultFileName) : null, __pendingDefaultFileName);
+			__pendingDownload = false;
+			__pendingDefaultFileName = null;
+		}		
+		#end
+		#end
+
 		dispatchEvent(event);
 	}
 
@@ -1520,6 +1539,13 @@ class FileReference extends EventDispatcher
 
 	@:noCompletion private function urlLoader_onIOError(event:IOErrorEvent):Void
 	{
+		#if(js && html5)
+		if(__pendingDownload){
+			__pendingDownload = false;
+			__pendingDefaultFileName = null;
+		}		
+		#end
+
 		dispatchEvent(event);
 	}