Package-ify Dromaeo and browser controller functionality

samples/third_party/dromaeo/web/htmlrunner.js

 // An version of Dromaeo's original htmlrunner adapted for the
 // Dart-based test driver.
 
 var _operations = [];
 var _N_RUNS = 5;
 var _nRanTests = 0;
 var _nTests = 0;
 var _T_DISTRIBUTION = 2.776;
 
 function startTest() {
@@ skipping 122 matching lines @@
           });
 }
 
 function endTest() {
   _postMessage('inited', { 'nTests': _nTests });
 }
 
 function prep(fn) {
   _operations.push(fn);
 }