Optimize DDC private library files.

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);
@@ skipping 28 matching lines @@
     get context() {
       return html.CanvasRenderingContext2D.as(sunflower.canvas[dartx.getContext]('2d'));
     },
     get slider() {
       return html.InputElement.as(sunflower.querySelector("#slider"));
     },
     get notes() {
       return sunflower.querySelector("#notes");
     },
     get PHI() {
-      return (dart.notNull(math.sqrt(5)) + 1) / 2;
+      return (math.sqrt(5) + 1) / 2;
     },
     get seeds() {
       return 0;
     },
     set seeds(_) {}
   });
   sunflower.main = function() {
     sunflower.slider[dartx.addEventListener]('change', dart.fn(e => sunflower.draw(), EventTovoid()));
     sunflower.draw();
   };
   dart.fn(sunflower.main, VoidTovoid());
   sunflower.draw = function() {
     sunflower.seeds = core.int.parse(sunflower.slider.value);
     sunflower.context.clearRect(0, 0, sunflower.MAX_D, sunflower.MAX_D);
     for (let i = 0; i < dart.notNull(sunflower.seeds); i++) {
       let theta = i * painter.TAU / dart.notNull(sunflower.PHI);
-      let r = dart.notNull(math.sqrt(i)) * sunflower.SCALE_FACTOR;
-      let x = sunflower.centerX + r * dart.notNull(math.cos(theta));
-      let y = sunflower.centerY - r * dart.notNull(math.sin(theta));
+      let r = math.sqrt(i) * sunflower.SCALE_FACTOR;
+      let x = sunflower.centerX + r * math.cos(theta);
+      let y = sunflower.centerY - r * math.sin(theta);
       new sunflower.SunflowerSeed.new(x, y, sunflower.SEED_RADIUS).draw(sunflower.context);
     }
     sunflower.notes[dartx.text] = dart.str`${sunflower.seeds} seeds`;
   };
   dart.fn(sunflower.draw, VoidTovoid());
   circle.Circle = class Circle extends core.Object {
     get x() {
       return this[x$];
     }
     set x(value) {
@@ skipping 93 matching lines @@
   }, null);
   // Exports:
   return {
     sunflower: sunflower,
     circle: circle,
     painter: painter
   };
 });
 
 //# sourceMappingURL=sunflower.js.map