Decrease dependence of SecondaryToolbar on UI buttons

web/secondary_toolbar.js

@@ -25,11 +25,10 @@ var SecondaryToolbar = {
 
   initialize: function secondaryToolbarInitialize(options) {
     this.toolbar = options.toolbar;
-    this.toggleButton = options.toggleButton;
-
     this.buttonContainer = this.toolbar.firstElementChild;
 
     // Define the toolbar buttons.
+    this.toggleButton = options.toggleButton;
     this.presentationMode = options.presentationMode;
     this.openFile = options.openFile;
     this.print = options.print;
@@ -40,21 +39,24 @@ var SecondaryToolbar = {
     this.pageRotateCcw = options.pageRotateCcw;
 
     // Attach the event listeners.
-    this.toggleButton.addEventListener('click', this.toggle.bind(this));
-
-    this.presentationMode.addEventListener('click',
-      this.presentationModeClick.bind(this));
-    this.openFile.addEventListener('click', this.openFileClick.bind(this));
-    this.print.addEventListener('click', this.printClick.bind(this));
-    this.download.addEventListener('click', this.downloadClick.bind(this));
-
-    this.firstPage.addEventListener('click', this.firstPageClick.bind(this));
-    this.lastPage.addEventListener('click', this.lastPageClick.bind(this));
-
-    this.pageRotateCw.addEventListener('click',
-      this.pageRotateCwClick.bind(this));
-    this.pageRotateCcw.addEventListener('click',
-      this.pageRotateCcwClick.bind(this));
+    var elements = [
+      { element: this.toggleButton, handler: this.toggle },
+      { element: this.presentationMode, handler: this.presentationModeClick },
+      { element: this.openFile, handler: this.openFileClick },
+      { element: this.print, handler: this.printClick },
+      { element: this.download, handler: this.downloadClick },
+      { element: this.firstPage, handler: this.firstPageClick },
+      { element: this.lastPage, handler: this.lastPageClick },
+      { element: this.pageRotateCw, handler: this.pageRotateCwClick },
+      { element: this.pageRotateCcw, handler: this.pageRotateCcwClick }
+    ];
+
+    for (var item in elements) {
+      var element = elements[item].element;
+      if (element) {
+        element.addEventListener('click', elements[item].handler.bind(this));
+      }
+    }
   },
 
   // Event handling functions.