fix(chips): fix chips focus functionality

- The normal mobile devices won't trigger the focus on the element.
Focusing the element on `ng-click` fixes that issue.
Through keeping and redirecting to `ng-focus` it's still possible to select chips through keyboard
- At the moment, we only reset the selectedChip variable but we don't
  apply that to the view, so we need to run an async evaluation.

Fixes #5897 Fixes #5662

src/components/chips/chips.spec.js

@@ -409,6 +409,59 @@ describe('<md-chips>', function() {
         }));
       });
 
+      describe('focus functionality', function() {
+        var element, ctrl;
+
+        beforeEach(function() {
+          element = buildChips(CHIP_SELECT_TEMPLATE);
+          ctrl = element.controller('mdChips');
+          document.body.appendChild(element[0]);
+        });
+
+        afterEach(function() {
+          element.remove();
+          element = ctrl = null;
+        });
+
+        it('should focus the chip when clicking / touching on the chip', function() {
+          scope.selectChip = jasmine.createSpy('clickChipSpy');
+
+          var chips = getChipElements(element);
+          expect(chips.length).toBe(3);
+
+          chips[0].children[0].click();
+
+          expect(scope.selectChip).toHaveBeenCalledTimes(1);
+        });
+
+        it('should focus the chip through normal content focus', function() {
+          scope.selectChip = jasmine.createSpy('focusChipSpy');
+          var chips = getChipElements(element);
+          expect(chips.length).toBe(3);
+
+          chips[0].children[0].focus();
+
+          expect(scope.selectChip).toHaveBeenCalledTimes(1);
+        });
+
+        it('should blur the chip correctly', function() {
+          var chips = getChipElements(element);
+          expect(chips.length).toBe(3);
+
+          var chipContent = chips[0].children[0];
+          chipContent.focus();
+
+          expect(ctrl.selectedChip).toBe(0);
+
+          chipContent.blur();
+
+          scope.$digest();
+
+          expect(ctrl.selectedChip).toBe(-1);
+        });
+
+      });
+
       describe('md-autocomplete', function() {
         var AUTOCOMPLETE_CHIPS_TEMPLATE = '\
           <md-chips ng-model="items">\

src/components/chips/js/chipDirective.js

@@ -52,7 +52,9 @@ function MdChip($mdTheming, $mdUtil) {
 
       if (ctrl) angular.element(element[0].querySelector('.md-chip-content'))
           .on('blur', function () {
-            ctrl.selectedChip = -1;
+            ctrl.$scope.$evalAsync(function() {
+              ctrl.resetSelectedChip();
+            });
           });
     };
   }

src/components/chips/js/chipsDirective.js

@@ -109,6 +109,7 @@
           <div class="md-chip-content"\
               tabindex="-1"\
               aria-hidden="true"\
+              ng-click="!$mdChipsCtrl.readonly && $mdChipsCtrl.focusChip($index)"\
               ng-focus="!$mdChipsCtrl.readonly && $mdChipsCtrl.selectChip($index)"\
               md-chip-transclude="$mdChipsCtrl.chipContentsTemplate"></div>\
           <div ng-if="!$mdChipsCtrl.readonly"\