Gif export panel first draft

js/service/ImageUploadService.js

@@ -0,0 +1,34 @@
+(function () {
+  var ns = $.namespace("pskl.service");
+  ns.ImageUploadService = function () {
+    this.serviceUrl_ = "http://screenletstore.appspot.com/__/upload";
+  };
+
+  ns.ImageUploadService.prototype.init = function () {
+    // service interface 
+  };
+
+  /**
+   * Upload a base64 image data to distant service. If successful, will call provided callback with the image URL as first argument;
+   * @param {String} imageData base64 image data (such as the return value of canvas.toDataUrl())
+   * @param {Function} cbSuccess success callback. 1st argument will be the uploaded image URL
+   * @param {Function} cbError error callback 
+   */
+  ns.ImageUploadService.prototype.upload = function (imageData, cbSuccess, cbError) {
+    var xhr = new XMLHttpRequest();
+    var formData = new FormData();
+    formData.append('data', imageData);
+    xhr.open('POST', this.serviceUrl_, true);
+    xhr.onload = function (e) {
+      if (this.status == 200) {
+        var imageUrl = "http://screenletstore.appspot.com/img/" + this.responseText; 
+        cbSuccess(imageUrl);
+      } else {
+        cbError();
+      }
+    };
+
+    xhr.send(formData);
+  };
+  
+})();