feat(aria): add provider to disable console warnings.

Fixes #3507.

src/core/services/aria/aria.js

@@ -1,11 +1,60 @@
+/**
+ * @ngdoc module
+ * @name material.core.aria
+ * @description
+ * Aria Expectations for ngMaterial components.
+ */
+angular
+  .module('material.core')
+  .provider('$mdAria', MdAriaProvider);
+
+/**
+ * Whether we should show ARIA warnings in the console, if labels are missing on the element
+ * By default the warnings are enabled
+ */
+var showWarnings = true;
+
+
+/**
+ * @ngdoc service
+ * @name $mdAriaProvider
+ * @module material.core.aria
+ *
+ * @description
+ *
+ * Modify options of the `$mdAria` service, which will be used by most of the Angular Material components.
+ **
+ *
+ * You are able to disable `$mdAria` warnings, by using the following markup.
+ * <hljs lang="js">
+ *   app.config(function($mdAriaProvider) {
+ *     // Globally disables all ARIA warnings.
+ *     $mdAriaProvider.disableWarnings();
+ *   });
+ * </hljs>
+ *
+ */
+function MdAriaProvider() {
 
-angular.module('material.core')
-  .service('$mdAria', AriaService);
+  return {
+    disableWarnings: disableWarnings,
+    $get: MdAriaService
+  };
+
+  /**
+   * @ngdoc method
+   * @name $mdAriaProvider#disableWarnings
+   * @param {boolean} disable Whether to show `$mdAria` console warnings. Default value is `false`.
+   */
+  function disableWarnings(disable) {
+    showWarnings = !disable || false;
+  }
+}
 
 /*
  * @ngInject
  */
-function AriaService($$rAF, $log, $window, $interpolate) {
+function MdAriaService($$rAF, $log, $window, $interpolate) {
 
   return {
     expect: expect,
@@ -32,7 +81,7 @@ function AriaService($$rAF, $log, $window, $interpolate) {
       defaultValue = angular.isString(defaultValue) ? defaultValue.trim() : '';
       if (defaultValue.length) {
         element.attr(attrName, defaultValue);
-      } else {
+      } else if (showWarnings) {
         $log.warn('ARIA: Attribute "', attrName, '", required for accessibility, is missing on node:', node);
       }
 

src/core/services/aria/aria.spec.js

@@ -1,7 +1,12 @@
 describe('$mdAria service', function() {
-  beforeEach(module('material.core'));
 
-  describe('expecting attributes', function(){
+  var $mdAriaProvider;
+
+  beforeEach(module('material.core', function($injector) {
+    $mdAriaProvider = $injector.get('$mdAriaProvider');
+  }));
+
+  describe('expecting attributes', function() {
     it('should warn if an invalid element is specified', inject(function($compile, $rootScope, $log, $mdAria) {
       spyOn($log, 'warn');
       var target = $compile('<div></div>')($rootScope);
@@ -28,7 +33,23 @@ describe('$mdAria service', function() {
       expect($log.warn).toHaveBeenCalled();
     }));
 
-    it('should warn if element is emtpry attribute', inject(function($compile, $rootScope, $log, $mdAria) {
+    it('should not warn if warnings are disabled', inject(function($compile, $rootScope, $log, $mdAria) {
+      spyOn($log, 'warn');
+      var button = $compile('<button aria-label><md-icon></md-icon></button>')($rootScope);
+
+      $mdAriaProvider.disableWarnings();
+
+      // We are able to use the injected $mdAria service, because the service reads its option from
+      // a global variable.
+      $mdAria.expect(button, 'aria-label');
+
+      expect($log.warn).toHaveBeenCalled();
+
+      // Reset our provider, because it will be used for the upcoming tests as well.
+      $mdAriaProvider.disableWarnings(false);
+    }));
+
+    it('should warn if element is empty attribute', inject(function($compile, $rootScope, $log, $mdAria) {
       spyOn($log, 'warn');
       var button = $compile('<button aria-label=""><md-icon></md-icon></button>')($rootScope);