simplify function coercions -- DDC can generate function types in place

lib/runtime/dart/convert.js

 dart_library.library('dart/convert', null, /* Imports */[
   'dart/_runtime',
   'dart/core',
   'dart/async',
   'dart/typed_data',
   'dart/_internal',
   'dart/collection'
 ], /* Lazy imports */[
 ], function(exports, dart, core, async, typed_data, _internal, collection) {
   'use strict';
@@ skipping 801 matching lines @@
     decode(source, opts) {
       let reviver = opts && 'reviver' in opts ? opts.reviver : null;
       if (reviver == null) reviver = this[_reviver];
       if (reviver == null) return this.decoder.convert(source);
       return new JsonDecoder(reviver).convert(source);
     }
     encode(value, opts) {
       let toEncodable = opts && 'toEncodable' in opts ? opts.toEncodable : null;
       if (toEncodable == null) toEncodable = this[_toEncodable$];
       if (toEncodable == null) return this.encoder.convert(value);
-      return new JsonEncoder(dart.as(toEncodable, __CastType0)).convert(value);
+      return new JsonEncoder(dart.as(toEncodable, dart.functionType(core.Object, [core.Object]))).convert(value);
     }
     get encoder() {
       if (this[_toEncodable$] == null) return dart.const(new JsonEncoder());
       return new JsonEncoder(dart.as(this[_toEncodable$], dart.functionType(core.Object, [core.Object])));
     }
     get decoder() {
       if (this[_reviver] == null) return dart.const(new JsonDecoder());
       return new JsonDecoder(this[_reviver]);
     }
   }
@@ skipping 18 matching lines @@
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }
     withIndent(indent, toEncodable) {
       if (toEncodable === void 0) toEncodable = null;
       this.indent = indent;
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }
     convert(object) {
-      return _JsonStringStringifier.stringify(object, dart.as(this[_toEncodable$], __CastType2), this.indent);
+      return _JsonStringStringifier.stringify(object, dart.as(this[_toEncodable$], dart.functionType(dart.dynamic, [dart.dynamic])), this.indent);
     }
     startChunkedConversion(sink) {
       if (!dart.is(sink, StringConversionSink)) {
         sink = StringConversionSink.from(sink);
       } else if (dart.is(sink, _Utf8EncoderSink)) {
         return new _JsonUtf8EncoderSink(sink[_sink], this[_toEncodable$], JsonUtf8Encoder._utf8Encode(this.indent), JsonUtf8Encoder.DEFAULT_BUFFER_SIZE);
       }
       return new _JsonEncoderSink(dart.as(sink, StringConversionSink), this[_toEncodable$], this.indent);
     }
     bind(stream) {
       return super.bind(stream);
     }
     fuse(other) {
       if (dart.is(other, Utf8Encoder)) {
-        return new JsonUtf8Encoder(this.indent, dart.as(this[_toEncodable$], __CastType4));
+        return new JsonUtf8Encoder(this.indent, dart.as(this[_toEncodable$], dart.functionType(dart.dynamic, [core.Object])));
       }
       return super.fuse(other);
     }
   }
   dart.defineNamedConstructor(JsonEncoder, 'withIndent');
   dart.setSignature(JsonEncoder, {
     constructors: () => ({
       JsonEncoder: [JsonEncoder, [], [dart.functionType(core.Object, [core.Object])]],
       withIndent: [JsonEncoder, [core.String], [dart.functionType(core.Object, [core.Object])]]
     }),
@@ skipping 627 matching lines @@
             this.writeByte(indent[dartx.get](i));
           }
         }
       }
     }
   }
   dart.setSignature(_JsonUtf8StringifierPretty, {
     constructors: () => ({_JsonUtf8StringifierPretty: [_JsonUtf8StringifierPretty, [dart.dynamic, core.List$(core.int), dart.dynamic, dart.dynamic]]}),
     methods: () => ({writeIndentation: [dart.void, [core.int]]})
   });
-  const __CastType0 = dart.typedef('__CastType0', () => dart.functionType(core.Object, [core.Object]));
-  const __CastType2 = dart.typedef('__CastType2', () => dart.functionType(dart.dynamic, [dart.dynamic]));
-  const __CastType4 = dart.typedef('__CastType4', () => dart.functionType(dart.dynamic, [core.Object]));
   class Latin1Codec extends Encoding {
     Latin1Codec(opts) {
       let allowInvalid = opts && 'allowInvalid' in opts ? opts.allowInvalid : false;
       this[_allowInvalid] = allowInvalid;
       super.Encoding();
     }
     get name() {
       return "iso-8859-1";
     }
     decode(bytes, opts) {
@@ skipping 1291 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.Utf8Codec = Utf8Codec;
   exports.UTF8 = UTF8;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
 });