title: Error: 'reflect-metadata shim is required' when upgrading to Webpack 2
body: <p>My team and I are trying to upgrade our code base to Webpack 2 and we are stuck with these two errors :</p>
  
  <p>'Uncaught reflect-metadata shim is required when using class decorators' &amp; 'Cannot read property 'isDefaultChangeDetectionStrategy' of undefined'</p>
  
  <p>We are working with the <a href="https://github.com/AngularClass/angular2-webpack-starter" rel="nofollow">angular2-webpack-starter</a>, are up to date with RC5, and are trying to make this update.</p>
  
  <p>We believe the error is coming from the polyfills.browser.ts file, in which we have this code:</p>
  
  <pre><code>import 'core-js/es6/symbol';
  import 'core-js/es6/object';
  import 'core-js/es6/function';
  import 'core-js/es6/parse-int';
  import 'core-js/es6/parse-float';
  import 'core-js/es6/number';
  import 'core-js/es6/math';
  import 'core-js/es6/string';
  import 'core-js/es6/date';
  import 'core-js/es6/array';
  import 'core-js/es6/regexp';
  import 'core-js/es6/map';
  import 'core-js/es6/set';
  import 'core-js/es6/weak-map';
  import 'core-js/es6/weak-set';
  import 'core-js/es6/typed';
  import 'core-js/es6/reflect';
  // see issue https://github.com/AngularClass/angular2-webpack-starter/issues/709
  // import 'core-js/es6/promise';
  
  import 'core-js/es7/reflect';
  import 'zone.js/dist/zone';
  
  // Typescript emit helpers polyfill
  import 'ts-helpers';
  
  if ('production' === ENV) {
    // Production
  
  
  } else {
    // Development
  
    Error.stackTraceLimit = Infinity;
  
    require('zone.js/dist/long-stack-trace-zone');
  
  }
  </code></pre>
  
  <p>Also, our webpack.common.js entry obj inside module.exports looks like this:</p>
  
  <pre><code>module.exports = {
      {...},
      entry: {
          'polyfills': './src/polyfills.browser.ts',
          'vendor': './src/vendor.browser.ts',
          'main': './src/main.browser.ts'
       },
       {...}
   }
  </code></pre>
  
  <p>Any help is greatly appreciated!</p>