Roll third_party/polymer.

third_party/polymer/v1_0/components-chromium/paper-tabs/paper-tabs-extracted.js

 Polymer({
       is: 'paper-tabs',
 
       behaviors: [
         Polymer.IronResizableBehavior,
         Polymer.IronMenubarBehavior
       ],
 
       properties: {
         /**
@@ skipping 53 matching lines @@
         alignBottom: {
           type: Boolean,
           value: false
         },
 
         selectable: {
           type: String,
           value: 'paper-tab'
         },
 
+        /**
+         * If true, tabs are automatically selected when focused using the
+         * keyboard.
+         */
+        autoselect: {
+          type: Boolean,
+          value: false
+        },
+
+        /**
+         * The delay (in milliseconds) between when the user stops interacting
+         * with the tabs through the keyboard and when the focused item is
+         * automatically selected (if `autoselect` is true).
+         */
+        autoselectDelay: {
+          type: Number,
+          value: 0
+        },
+
         _step: {
           type: Number,
           value: 10
         },
 
         _holdDelay: {
           type: Number,
           value: 1
         },
 
@@ skipping 16 matching lines @@
         role: 'tablist'
       },
 
       listeners: {
         'iron-resize': '_onTabSizingChanged',
         'iron-items-changed': '_onTabSizingChanged',
         'iron-select': '_onIronSelect',
         'iron-deselect': '_onIronDeselect'
       },
 
+      keyBindings: {
+        'left:keyup right:keyup': '_onArrowKeyup'
+      },
+
       created: function() {
         this._holdJob = null;
+        this._pendingActivationItem = undefined;
+        this._pendingActivationTimeout = undefined;
+        this._bindDelayedActivationHandler = this._delayedActivationHandler.bind(this);
+        this.addEventListener('blur', this._onBlurCapture.bind(this), true);
       },
 
       ready: function() {
         this.setScrollDirection('y', this.$.tabsContainer);
       },
 
+      detached: function() {
+        this._cancelPendingActivation();
+      },
+
       _noinkChanged: function(noink) {
         var childTabs = Polymer.dom(this).querySelectorAll('paper-tab');
         childTabs.forEach(noink ? this._setNoinkAttribute : this._removeNoinkAttribute);
       },
 
       _setNoinkAttribute: function(element) {
         element.setAttribute('noink', '');
       },
 
       _removeNoinkAttribute: function(element) {
@@ skipping 41 matching lines @@
         this.cancelDebouncer('tab-changed');
       },
 
       _onIronDeselect: function(event) {
         this.debounce('tab-changed', function() {
           this._tabChanged(null, this._previousTab);
         // See polymer/polymer#1305
         }, 1);
       },
 
+      _activateHandler: function() {
+        // Cancel item activations scheduled by keyboard events when any other
+        // action causes an item to be activated (e.g. clicks).
+        this._cancelPendingActivation();
+
+        Polymer.IronMenuBehaviorImpl._activateHandler.apply(this, arguments);
+      },
+
+      /**
+       * Activates an item after a delay (in milliseconds).
+       */
+      _scheduleActivation: function(item, delay) {
+        this._pendingActivationItem = item;
+        this._pendingActivationTimeout = this.async(
+            this._bindDelayedActivationHandler, delay);
+      },
+
+      /**
+       * Activates the last item given to `_scheduleActivation`.
+       */
+      _delayedActivationHandler: function() {
+        var item = this._pendingActivationItem;
+        this._pendingActivationItem = undefined;
+        this._pendingActivationTimeout = undefined;
+        item.fire(this.activateEvent, null, {
+          bubbles: true,
+          cancelable: true
+        });
+      },
+
+      /**
+       * Cancels a previously scheduled item activation made with
+       * `_scheduleActivation`.
+       */
+      _cancelPendingActivation: function() {
+        if (this._pendingActivationTimeout !== undefined) {
+          this.cancelAsync(this._pendingActivationTimeout);
+          this._pendingActivationItem = undefined;
+          this._pendingActivationTimeout = undefined;
+        }
+      },
+
+      _onArrowKeyup: function(event) {
+        if (this.autoselect) {
+          this._scheduleActivation(this.focusedItem, this.autoselectDelay);
+        }
+      },
+
+      _onBlurCapture: function(event) {
+        // Cancel a scheduled item activation (if any) when that item is
+        // blurred.
+        if (event.target === this._pendingActivationItem) {
+          this._cancelPendingActivation();
+        }
+      },
+
       get _tabContainerScrollSize () {
         return Math.max(
           0,
           this.$.tabsContainer.scrollWidth -
             this.$.tabsContainer.offsetWidth
         );
       },
 
-
       _scroll: function(e, detail) {
         if (!this.scrollable) {
           return;
         }
 
         var ddx = (detail && -detail.ddx) || 0;
         this._affectScroll(ddx);
       },
 
       _down: function(e) {
@@ skipping 121 matching lines @@
         if (cl.contains('expand')) {
           cl.remove('expand');
           cl.add('contract');
           this._positionBar(this._pos.width, this._pos.left);
         // bar animation done
         } else if (cl.contains('contract')) {
           cl.remove('contract');
         }
       }
     });