fix(backButton): dynamic icon/text updates

Allow back button icon/text to be updated after app initialization.
Closes #3281

Author: adamdbradley

Diff for: js/angular/controller/headerBarController.js

@@ -74,10 +74,31 @@ function($scope, $element, $attrs, $q, $ionicConfig, $ionicHistory) {
 
 
   self.updateBackButton = function() {
+    var ele;
     if ((isBackShown && isNavBackShown && isBackEnabled) !== isBackElementShown) {
       isBackElementShown = isBackShown && isNavBackShown && isBackEnabled;
-      var backBtnEle = getEle(BACK_BUTTON);
-      backBtnEle && backBtnEle.classList[ isBackElementShown ? 'remove' : 'add' ](HIDE);
+      ele = getEle(BACK_BUTTON);
+      ele && ele.classList[ isBackElementShown ? 'remove' : 'add' ](HIDE);
+    }
+
+    if (isBackEnabled) {
+      ele = ele || getEle(BACK_BUTTON);
+      if (ele) {
+        if (self.backButtonIcon !== $ionicConfig.backButton.icon()) {
+          ele = getEle(BACK_BUTTON + ' .icon');
+          if (ele) {
+            self.backButtonIcon = $ionicConfig.backButton.icon();
+            ele.className = 'icon ' + self.backButtonIcon;
+          }
+        }
+
+        if (self.backButtonText !== $ionicConfig.backButton.text()) {
+          ele = getEle(BACK_BUTTON + ' .back-text');
+          if (ele) {
+            ele.textContent = self.backButtonText = $ionicConfig.backButton.text();
+          }
+        }
+      }
     }
   };
 

Diff for: js/angular/controller/navBarController.js

@@ -55,7 +55,6 @@ function($scope, $element, $attrs, $compile, $timeout, $ionicNavBarDelegate, $io
     var lastViewItemEle = {};
     var leftButtonsEle, rightButtonsEle;
 
-    //navEle[BACK_BUTTON] = self.createBackButtonElement(headerBarEle);
     navEle[BACK_BUTTON] = createNavElement(BACK_BUTTON);
     navEle[BACK_BUTTON] && headerBarEle.append(navEle[BACK_BUTTON]);
 
@@ -79,6 +78,8 @@ function($scope, $element, $attrs, $compile, $timeout, $ionicNavBarDelegate, $io
     $element.append($compile(containerEle)($scope.$new()));
 
     var headerBarCtrl = headerBarEle.data('$ionHeaderBarController');
+    headerBarCtrl.backButtonIcon = $ionicConfig.backButton.icon();
+    headerBarCtrl.backButtonText = $ionicConfig.backButton.text();
 
     var headerBarInstance = {
       isActive: isActive,