Revert "Revert "fix #27256, track type bounds for generic functions""

pkg/dev_compiler/test/codegen_expected/sunflower/sunflower.js

 define(['dart_sdk'], function(dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const html = dart_sdk.html;
   const math = dart_sdk.math;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const sunflower = Object.create(null);
   const circle = Object.create(null);
   const painter = Object.create(null);
-  let StringToElement = () => (StringToElement = dart.constFn(dart.definiteFunctionType(html.Element, [core.String])))();
-  let EventTovoid = () => (EventTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [html.Event])))();
-  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
+  let StringToElement = () => (StringToElement = dart.constFn(dart.fnType(html.Element, [core.String])))();
+  let EventTovoid = () => (EventTovoid = dart.constFn(dart.fnType(dart.void, [html.Event])))();
+  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.fnType(dart.void, [])))();
   dart.defineLazy(sunflower, {
     get SEED_RADIUS() {
       return 2;
     },
     get SCALE_FACTOR() {
       return 4;
     },
     get MAX_D() {
       return 300;
     },
@@ skipping 100 matching lines @@
       context[dartx.arc](this.x, this.y, this.radius, 0, painter.TAU, false);
       context[dartx.fill]();
       context.closePath();
       context.stroke();
     }
   };
   const color = Symbol("CirclePainter.color");
   painter.CirclePainter[dart.implements] = () => [circle.Circle];
   dart.setSignature(painter.CirclePainter, {
     fields: () => ({color: dart.fieldType(core.String)}),
-    methods: () => ({draw: dart.definiteFunctionType(dart.void, [html.CanvasRenderingContext2D])})
+    methods: () => ({draw: dart.fnType(dart.void, [html.CanvasRenderingContext2D])})
   });
   sunflower.SunflowerSeed = class SunflowerSeed extends dart.mixin(circle.Circle, painter.CirclePainter) {
     new(x, y, radius, color) {
       if (color === void 0) color = null;
       super.new(x, y, radius);
       if (color != null) this.color = color;
     }
   };
   dart.defineLazy(painter, {
     get ORANGE() {
@@ skipping 28 matching lines @@
   }, null);
   // Exports:
   return {
     sunflower: sunflower,
     circle: circle,
     painter: painter
   };
 });
 
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