Bug 580422 - Test Pilot Raw Data log randomly resets. r+a=dtownsend

browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/setup.js

@@ -570,7 +570,7 @@ let TestPilotSetup = {
 	      task.defaultUrl, false, function() {
                 /* on close callback (Bug 575767) -- when the "new study
                  * starting" popup is dismissed, then the study can start. */
-                task.changeStatus(TaskConstants.STATUS_IN_PROGRESS, true);
+                task.changeStatus(TaskConstants.STATUS_STARTING, true);
                 TestPilotSetup.reloadRemoteExperiments();
               });
             return;

browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/tasks.js

@@ -619,11 +619,14 @@ TestPilotExperiment.prototype = {
       if (uuid.indexOf("{") == 0) {
         uuid = uuid.substring(1, (uuid.length - 1));
       }
-      // clear the data before starting.
-      this._dataStore.wipeAllData();
-      this.changeStatus(TaskConstants.STATUS_STARTING, true);
       Application.prefs.setValue(GUID_PREF_PREFIX + this._id, uuid);
-      this.onExperimentStartup();
+      // clear the data before starting.
+      let self = this;
+      this._dataStore.wipeAllData(function() {
+        // Experiment is now in progress.
+        self.changeStatus(TaskConstants.STATUS_IN_PROGRESS, true);
+        self.onExperimentStartup();
+      });
     }
 
     // What happens when a test finishes: