Implement modular compilation

test/codegen/expect/collection/src/iterable_zip.js

-dart_library.library('collection/src/iterable_zip', null, /* Imports */[
-  'dart/_runtime',
-  'dart/core',
-  'dart/collection'
-], /* Lazy imports */[
-], function(exports, dart, core, collection) {
-  'use strict';
-  let dartx = dart.dartx;
-  const _iterables = Symbol('_iterables');
-  const IterableZip$ = dart.generic(function(T) {
-    class IterableZip extends collection.IterableBase$(core.List$(T)) {
-      IterableZip(iterables) {
-        this[_iterables] = iterables;
-        super.IterableBase();
-      }
-      get iterator() {
-        let iterators = this[_iterables][dartx.map](dart.fn(x => {
-          dart.as(x, core.Iterable$(T));
-          return x[dartx.iterator];
-        }, core.Iterator$(T), [core.Iterable$(T)]))[dartx.toList]({growable: false});
-        return new (_IteratorZip$(T))(iterators);
-      }
-    }
-    dart.setSignature(IterableZip, {
-      constructors: () => ({IterableZip: [IterableZip$(T), [core.Iterable$(core.Iterable$(T))]]})
-    });
-    dart.defineExtensionMembers(IterableZip, ['iterator']);
-    return IterableZip;
-  });
-  let IterableZip = IterableZip$();
-  const _iterators = Symbol('_iterators');
-  const _current = Symbol('_current');
-  const _IteratorZip$ = dart.generic(function(T) {
-    class _IteratorZip extends core.Object {
-      _IteratorZip(iterators) {
-        this[_iterators] = iterators;
-        this[_current] = null;
-      }
-      moveNext() {
-        if (dart.notNull(this[_iterators][dartx.isEmpty])) return false;
-        for (let i = 0; i < dart.notNull(this[_iterators][dartx.length]); i++) {
-          if (!dart.notNull(this[_iterators][dartx.get](i).moveNext())) {
-            this[_current] = null;
-            return false;
-          }
-        }
-        this[_current] = core.List$(T).new(this[_iterators][dartx.length]);
-        for (let i = 0; i < dart.notNull(this[_iterators][dartx.length]); i++) {
-          this[_current][dartx.set](i, this[_iterators][dartx.get](i).current);
-        }
-        return true;
-      }
-      get current() {
-        return this[_current];
-      }
-    }
-    _IteratorZip[dart.implements] = () => [core.Iterator$(core.List$(T))];
-    dart.setSignature(_IteratorZip, {
-      constructors: () => ({_IteratorZip: [_IteratorZip$(T), [core.List$(core.Iterator$(T))]]}),
-      methods: () => ({moveNext: [core.bool, []]})
-    });
-    return _IteratorZip;
-  });
-  let _IteratorZip = _IteratorZip$();
-  // Exports:
-  exports.IterableZip$ = IterableZip$;
-  exports.IterableZip = IterableZip;
-});