fix(icons): improve use of material-icons style

Improve logic to auto-add `.material-icons` style to **md-icon**.
> NOTE: will not auto-add if using any class or ng-class attributes; see demoFontIconsWithLigatures

Fixes #3333.

Author: ThomasBurleson

src/components/icon/demoFontIconsWithLigatures/index.html

@@ -11,7 +11,7 @@
       <div class="preview-glyphs">
         <md-icon ng-style="{color: font.color}"
             aria-label="{{ font.name }}"
-            class="step"
+            class="material-icons step"
             ng-class="it.size">
           {{ font.name }}
         </md-icon>

src/components/icon/iconDirective.js

@@ -209,12 +209,23 @@ function mdIconDirective($mdIcon, $mdTheming, $mdAria, $interpolate ) {
 
     function prepareForFontIcon () {
       if (!scope.svgIcon && !scope.svgSrc) {
+
         if (scope.fontIcon) {
           element.addClass('md-font');
           element.addClass(scope.fontIcon);
-        } else {
+        }
+
+        if (scope.fontSet) {
           element.addClass($mdIcon.fontSet(scope.fontSet));
         }
+
+        // For Material Design font icons, the class '.material-icons'
+        // is auto-added IF a style has not been specified
+
+        if (!scope.fontIcon && !scope.fontSet && !angular.isDefined(attr.class)) {
+
+            element.addClass('material-icons');
+        }
       }
 
     }

src/components/icon/iconDirective.spec.js

@@ -1,4 +1,4 @@
-describe('mdIcon directive', function() {
+ddescribe('mdIcon directive', function() {
   var el;
   var $scope;
   var $compile;
@@ -11,6 +11,7 @@ describe('mdIcon directive', function() {
    }));
    afterEach( function() {
      $mdIconProvider.defaultFontSet('material-icons');
+     $mdIconProvider.fontSet('fa', 'fa');
    });
 
 
@@ -21,6 +22,7 @@ describe('mdIcon directive', function() {
         $compile = _$compile_;
     }));
 
+
     describe('using font-icons with deprecated md-font-icon=""', function() {
 
       it('should render correct HTML with md-font-icon value as class', function() {
@@ -64,7 +66,7 @@ describe('mdIcon directive', function() {
 
         expect(el.attr('md-font-icon')).toBe($scope.font.name);
         expect(el.hasClass('step')).toBe(true);
-        expect(el.hasClass('material-icons')).toBe(true);
+        expect(el.hasClass('material-icons')).toBe(false);
         expect(el.attr('aria-label')).toBe($scope.font.name + $scope.font.size);
         expect(el.attr('role')).toBe('img');
       })
@@ -77,7 +79,7 @@ describe('mdIcon directive', function() {
         el = make( '<md-icon class="md-48">face</md-icon>');
 
         expect(el.text()).toEqual('face');
-        expect(el.hasClass('material-icons')).toBeTruthy();
+        expect(el.hasClass('material-icons')).toBeFalsy();
         expect(el.hasClass('md-48')).toBeTruthy();
       });
 
@@ -90,6 +92,15 @@ describe('mdIcon directive', function() {
         expect( clean(el.attr('class')) ).toEqual("fontawesome");
       });
 
+
+      it('should render correctly using a md-font-set alias', function() {
+        el = make( '<md-icon md-font-set="fa" md-font-icon="fa-info"></md-icon>');
+
+        expect( clean(el.attr('class')) ).toEqual("md-font fa-info fa");
+      });
+
+
+
       it('should render correctly using md-font-set value as class', function() {
 
         el = make( '<md-icon md-font-set="fontawesome">email</md-icon>');
@@ -101,11 +112,19 @@ describe('mdIcon directive', function() {
 
     describe('using font-icons with classnames', function() {
 
+      it('should auto-add the material-icons style', function() {
+        el = make( '<md-icon>apple</md-icon>');
+
+        expect(el.text()).toEqual('apple');
+        expect(el.hasClass('material-icons')).toBeTruthy();
+      });
+
+
       it('should render with icon classname', function() {
         el = make( '<md-icon class="custom-cake"></md-icon>');
 
         expect(el.text()).toEqual('');
-        expect(el.hasClass('material-icons')).toBeTruthy();
+        expect(el.hasClass('material-icons')).toBeFalsy();
         expect(el.hasClass('custom-cake')).toBeTruthy();
       });