fix(chips): do not trim the input model.

* The chips input should not trim the text, because otherwise the buffer will be always falsey, even when there are spaces in the input, and this would cause the backspace not to work.

Fixes #7243

Closes #7748

# Conflicts:
#	src/components/chips/js/chipsController.js

src/components/chips/chips.spec.js

@@ -388,8 +388,59 @@ describe('<md-chips>', function() {
           expect(enterEvent.preventDefault).toHaveBeenCalled();
         }));
 
+        it('should trim the buffer when a chip will be added', inject(function($mdConstant) {
+          var element = buildChips(BASIC_CHIP_TEMPLATE);
+          var ctrl = element.controller('mdChips');
+          var input = element.find('input');
+
+          // This string contains a lot of spaces, which should be trimmed.
+          input.val('    Test    ');
+          input.triggerHandler('input');
+
+          expect(ctrl.chipBuffer).toBeTruthy();
+
+          var enterEvent = {
+            type: 'keydown',
+            keyCode: $mdConstant.KEY_CODE.ENTER,
+            which: $mdConstant.KEY_CODE.ENTER
+          };
+
+          input.triggerHandler(enterEvent);
+
+          expect(scope.items).toEqual(['Apple', 'Banana', 'Orange', 'Test']);
+        }));
+
+        it('should not trim the input text of the input', inject(function($mdConstant) {
+          var element = buildChips(BASIC_CHIP_TEMPLATE);
+          var ctrl = element.controller('mdChips');
+          var input = element.find('input');
+
+          input.val('    ');
+          input.triggerHandler('input');
+
+          expect(ctrl.chipBuffer).toBeTruthy();
+
+          var enterEvent = {
+            type: 'keydown',
+            keyCode: $mdConstant.KEY_CODE.BACKSPACE,
+            which: $mdConstant.KEY_CODE.BACKSPACE,
+            preventDefault: jasmine.createSpy('preventDefault')
+          };
+
+          input.triggerHandler(enterEvent);
+
+          expect(enterEvent.preventDefault).not.toHaveBeenCalled();
+
+          input.val('');
+          input.triggerHandler('input');
+
+          input.triggerHandler(enterEvent);
+
+          expect(enterEvent.preventDefault).toHaveBeenCalledTimes(1);
+        }));
       });
 
+
       it('focuses/blurs the component when focusing/blurring the input', inject(function() {
         var element = buildChips(BASIC_CHIP_TEMPLATE);
         var ctrl = element.controller('mdChips');

src/components/chips/js/chipsController.js

@@ -11,9 +11,10 @@ angular
  * @param $mdConstant
  * @param $log
  * @param $element
+ * @param $mdUtil
  * @constructor
  */
-function MdChipsCtrl ($scope, $mdConstant, $log, $element, $timeout) {
+function MdChipsCtrl ($scope, $mdConstant, $log, $element, $timeout, $mdUtil) {
   /** @type {$timeout} **/
   this.$timeout = $timeout;
 
@@ -50,6 +51,8 @@ function MdChipsCtrl ($scope, $mdConstant, $log, $element, $timeout) {
   /** @type {boolean} */
   this.hasAutocomplete = false;
 
+  /** @type {string} */
+  this.enableChipEdit = $mdUtil.parseAttributeBoolean(this.mdEnableChipEdit);
 
   /**
    * Hidden hint text for how to delete a chip. Used to give context to screen readers.
@@ -137,18 +140,47 @@ MdChipsCtrl.prototype.inputKeydown = function(event) {
   if (this.separatorKeys.indexOf(event.keyCode) !== -1) {
     if ((this.hasAutocomplete && this.requireMatch) || !chipBuffer) return;
     event.preventDefault();
-    this.appendChip(chipBuffer);
+
+    // Only append the chip and reset the chip buffer if the max chips limit isn't reached.
+    if (this.hasMaxChipsReached()) return;
+
+    this.appendChip(chipBuffer.trim());
     this.resetChipBuffer();
   }
 };
 
+
+/**
+ * Updates the content of the chip at given index
+ * @param chipIndex
+ * @param chipContents
+ */
+MdChipsCtrl.prototype.updateChipContents = function(chipIndex, chipContents){
+  if(chipIndex >= 0 && chipIndex < this.items.length) {
+    this.items[chipIndex] = chipContents;
+    this.ngModelCtrl.$setDirty();
+  }
+};
+
+
+/**
+ * Returns true if a chip is currently being edited. False otherwise.
+ * @return {boolean}
+ */
+MdChipsCtrl.prototype.isEditingChip = function(){
+  return !!this.$element[0].getElementsByClassName('_md-chip-editing').length;
+};
+
+
 /**
  * Handles the keydown event on the chip elements: backspace removes the selected chip, arrow
  * keys switch which chips is active
  * @param event
  */
 MdChipsCtrl.prototype.chipKeydown = function (event) {
   if (this.getChipBuffer()) return;
+  if (this.isEditingChip()) return;
+
   switch (event.keyCode) {
     case this.$mdConstant.KEY_CODE.BACKSPACE:
     case this.$mdConstant.KEY_CODE.DELETE:
@@ -242,7 +274,7 @@ MdChipsCtrl.prototype.appendChip = function(newChip) {
     var identical = this.items.some(function(item){
       return angular.equals(newChip, item);
     });
-    if(identical) return;
+    if (identical) return;
   }
 
   // Check for a null (but not undefined), or existing chip and cancel appending
@@ -251,6 +283,10 @@ MdChipsCtrl.prototype.appendChip = function(newChip) {
   // Append the new chip onto our list
   var index = this.items.push(newChip);
 
+  // Update model validation
+  this.ngModelCtrl.$setDirty();
+  this.validateModel();
+
   // If they provide the md-on-add attribute, notify them of the chip addition
   if (this.useOnAdd && this.onAdd) {
     this.onAdd({ '$chip': newChip, '$index': index });
@@ -350,13 +386,30 @@ MdChipsCtrl.prototype.resetChipBuffer = function() {
   }
 };
 
+MdChipsCtrl.prototype.hasMaxChipsReached = function() {
+  if (angular.isString(this.maxChips)) this.maxChips = parseInt(this.maxChips, 10) || 0;
+
+  return this.maxChips > 0 && this.items.length >= this.maxChips;
+};
+
+/**
+ * Updates the validity properties for the ngModel.
+ */
+MdChipsCtrl.prototype.validateModel = function() {
+  this.ngModelCtrl.$setValidity('md-max-chips', !this.hasMaxChipsReached());
+};
+
 /**
  * Removes the chip at the given index.
  * @param index
  */
 MdChipsCtrl.prototype.removeChip = function(index) {
   var removed = this.items.splice(index, 1);
 
+  // Update model validation
+  this.ngModelCtrl.$setDirty();
+  this.validateModel();
+
   if (removed && removed.length && this.useOnRemove && this.onRemove) {
     this.onRemove({ '$chip': removed[0], '$index': index });
   }
@@ -415,7 +468,7 @@ MdChipsCtrl.prototype.selectAndFocusChip = function(index) {
  * Call `focus()` on the chip at `index`
  */
 MdChipsCtrl.prototype.focusChip = function(index) {
-  this.$element[0].querySelector('md-chip[index="' + index + '"] .md-chip-content').focus();
+  this.$element[0].querySelector('md-chip[index="' + index + '"] ._md-chip-content').focus();
 };
 
 /**
@@ -479,10 +532,14 @@ MdChipsCtrl.prototype.configureUserInput = function(inputElement) {
 };
 
 MdChipsCtrl.prototype.configureAutocomplete = function(ctrl) {
-  if ( ctrl ){
+  if ( ctrl ) {
     this.hasAutocomplete = true;
+
     ctrl.registerSelectedItemWatcher(angular.bind(this, function (item) {
       if (item) {
+        // Only append the chip and reset the chip buffer if the max chips limit isn't reached.
+        if (this.hasMaxChipsReached()) return;
+
         this.appendChip(item);
         this.resetChipBuffer();
       }

src/components/chips/js/chipsDirective.js

@@ -131,6 +131,7 @@
             ng-model="$mdChipsCtrl.chipBuffer"\
             ng-focus="$mdChipsCtrl.onInputFocus()"\
             ng-blur="$mdChipsCtrl.onInputBlur()"\
+            ng-trim="false"\
             ng-keydown="$mdChipsCtrl.inputKeydown($event)">';
 
   var CHIP_DEFAULT_TEMPLATE = '\