JSON file of perf data can be saved from perf tab

js/controllers/PerfCtrl.js

@@ -6,7 +6,7 @@ panelApp.filter('sortByTime', function () {
   };
 });
 
-panelApp.controller('PerfCtrl', function PerfCtrl($scope, appContext) {
+panelApp.controller('PerfCtrl', function PerfCtrl($scope, appContext, filesystem) {
 
   $scope.enable = false;
 
@@ -17,6 +17,10 @@ panelApp.controller('PerfCtrl', function PerfCtrl($scope, appContext) {
     appContext.clearHistogram();
   };
 
+  $scope.exportData = function () {
+    filesystem.exportJSON('file.json', $scope.histogram);
+  };
+
   var first = true;
   $scope.$watch('enable', function (newVal, oldVal) {
 

js/services/filesystem.js

@@ -0,0 +1,32 @@
+// Service for exporting as JSON
+panelApp.factory('filesystem', function(chromeExtension) {
+
+  // taken from:
+  // http://html5-demos.appspot.com/static/html5storage/index.html#slide59
+
+  // TODO: error handlers?
+
+  return {
+    exportJSON: function (name, data) {
+      //TODO: file size/limits? 1024*1024
+       window.webkitRequestFileSystem(window.TEMPORARY, 1024*1024, function (fs) {
+        fs.root.getFile(name + '.json', {create: true}, function (fileEntry) {
+          fileEntry.createWriter(function(fileWriter) {
+
+            var builder = new WebKitBlobBuilder();
+            builder.append(JSON.stringify(data));
+            var blob = builder.getBlob('text/plain');
+
+            fileWriter.onwriteend = function () {
+              // navigate to file, will download
+              //location.href = fileEntry.toURL();
+              window.open(fileEntry.toURL());
+            };
+
+            fileWriter.write(blob);
+          }, function() {});
+        }, function() {});
+      }, function() {});
+    }
+  };
+});

panel.html

@@ -16,6 +16,7 @@
 
   <script src="js/services/appContext.js"></script>
   <script src="js/services/chromeExtension.js"></script>
+  <script src="js/services/filesystem.js"></script>
 
   <script src="js/controllers/OptionsCtrl.js"></script>
   <script src="js/controllers/PerfCtrl.js"></script>
@@ -84,7 +85,8 @@
           </div>
         </div>
       </div>
-      <button class="btn" ng-click="clearHistogram()">Clear Data</button>
+      <button class="btn btn-success" ng-click="exportData()">Save Data as JSON</button>
+      <button class="btn btn-danger" ng-click="clearHistogram()">Clear Data</button>
 
     </div>
   </div>