partially implement instance of checks and some codegen fixes

lib/runtime/dart/convert.js

 var convert;
 (function(exports) {
   'use strict';
   let ASCII = new AsciiCodec();
   let _ASCII_MASK = 127;
   let _allowInvalid = Symbol('_allowInvalid');
   let _nameToEncoding = Symbol('_nameToEncoding');
   let Codec$ = dart.generic(function(S, T) {
     class Codec extends core.Object {
       Codec() {
       }
       encode(input) {
         return this.encoder.convert(input);
       }
       decode(encoded) {
         return this.decoder.convert(encoded);
       }
       fuse(other) {
-        return new _FusedCodec(this, other);
+        return new (_FusedCodec$(S, T, dynamic))(this, other);
       }
       get inverted() {
-        return new _InvertedCodec(this);
+        return new (_InvertedCodec$(T, S))(this);
       }
     }
     return Codec;
   });
   let Codec = Codec$(dart.dynamic, dart.dynamic);
   class Encoding extends Codec$(core.String, core.List$(core.int)) {
     Encoding() {
       super.Codec();
     }
     decodeStream(byteStream) {
@@ skipping 37 matching lines @@
     get decoder() {
       return this[_allowInvalid] ? new AsciiDecoder({allowInvalid: true}) : new AsciiDecoder({allowInvalid: false});
     }
   }
   let _subsetMask = Symbol('_subsetMask');
   let Converter$ = dart.generic(function(S, T) {
     class Converter extends core.Object {
       Converter() {
       }
       fuse(other) {
-        return new _FusedConverter(this, other);
+        return new (_FusedConverter$(S, T, dynamic))(this, other);
       }
       startChunkedConversion(sink) {
         throw new core.UnsupportedError(`This converter does not support chunked conversions: ${this}`);
       }
       bind(source) {
         return new async.Stream.eventTransformed(source, ((sink) => new _ConverterStreamEventSink(this, sink)).bind(this));
       }
     }
     Converter[dart.implements] = () => [async.StreamTransformer];
     return Converter;
@@ skipping 1266 matching lines @@
       if (isLast) {
         this.close();
       }
     }
   }
   class LineSplitter extends Converter$(core.String, core.List$(core.String)) {
     LineSplitter() {
       super.Converter();
     }
     convert(data) {
-      let lines = new core.List();
+      let lines = new (core.List$(core.String))();
       _LineSplitterSink._addSlice(data, 0, data.length, true, lines.add);
       return lines;
     }
     startChunkedConversion(sink) {
       if (!dart.is(sink, StringConversionSink)) {
         sink = new StringConversionSink.from(sink);
       }
       return new _LineSplitterSink(dart.as(sink, StringConversionSink));
     }
   }
@@ skipping 984 matching lines @@
   exports.LineSplitter = LineSplitter;
   exports.StringConversionSink = StringConversionSink;
   exports.ClosableStringSink = ClosableStringSink;
   exports.UNICODE_REPLACEMENT_CHARACTER_RUNE = UNICODE_REPLACEMENT_CHARACTER_RUNE;
   exports.UNICODE_BOM_CHARACTER_RUNE = UNICODE_BOM_CHARACTER_RUNE;
   exports.UTF8 = UTF8;
   exports.Utf8Codec = Utf8Codec;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
 })(convert || (convert = {}));