refactor(benchamrks_external): Ts'ify benchmarks_external

Translates benchmarks_external to TypeScript.

modules/benchmarks_external/e2e_test/naive_infinite_scroll_perf.ts

@@ -0,0 +1,32 @@
+import {runBenchmark, verifyNoBrowserErrors} from 'angular2/src/test_lib/perf_util';
+
+describe('ng-dart1.x naive infinite scroll benchmark', function() {
+
+  var URL = 'benchmarks_external/src/naive_infinite_scroll/index.html';
+
+  afterEach(verifyNoBrowserErrors);
+
+  [1, 2, 4].forEach(function(appSize) {
+    it('should run scroll benchmark and collect stats for appSize = ' + appSize, function(done) {
+      runBenchmark({
+        url: URL,
+        id: 'ng1-dart1.x.naive_infinite_scroll',
+        work: function() {
+          $('#reset-btn').click();
+          $('#run-btn').click();
+          var s = 1000;
+          if (appSize > 4) {
+            s = s + appSize * 100;
+          }
+          browser.sleep(s);
+        },
+        params: [
+          {name: 'appSize', value: appSize},
+          {name: 'iterationCount', value: 20, scale: 'linear'},
+          {name: 'scrollIncrement', value: 40}
+        ]
+      }).then(done, done.fail);
+    });
+  });
+
+});