Upgrade to 1.0 and switch clients to dom-repeat where needed.

third_party/polymer/v0_8/components/iron-behaviors/iron-button-state.html

 <!--
+@license
 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 -->
 
 <link rel="import" href="../polymer/polymer.html">
+<link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
 <link rel="import" href="iron-control-state.html">
 
 <script>
 
-  Polymer.IronButtonState = {
+  /** @polymerBehavior Polymer.IronButtonState */
+  Polymer.IronButtonStateImpl = {
 
     properties: {
 
       /**
        * If true, the user is currently holding down the button.
        *
        * @attribute pressed
        * @type boolean
        * @default false
        */
       pressed: {
         type: Boolean,
         readOnly: true,
+        value: false,
         reflectToAttribute: true,
         observer: '_pressedChanged'
       },
 
       /**
        * If true, the button toggles the active state with each tap or press
        * of the spacebar.
        *
        * @attribute toggles
        * @type boolean
        * @default false
        */
       toggles: {
         type: Boolean,
+        value: false,
         reflectToAttribute: true
       },
 
       /**
        * If true, the button is a toggle and is currently in the active state.
        *
        * @attribute active
        * @type boolean
        * @default false
        */
       active: {
         type: Boolean,
+        value: false,
         notify: true,
         reflectToAttribute: true,
         observer: '_activeChanged'
+      },
+
+      /**
+       * True if the element is currently being pressed by a "pointer," which
+       * is loosely defined as mouse or touch input (but specifically excluding
+       * keyboard input).
+       */
+      pointerDown: {
+        type: Boolean,
+        readOnly: true,
+        value: false
+      },
+
+      /**
+       * True if the input device that caused the element to receive focus
+       * was a keyboard.
+       */
+      receivedFocusFromKeyboard: {
+        type: Boolean,
+        readOnly: true
       }
-
     },
 
     listeners: {
-      mousedown: '_downHandler',
-      mouseup: '_upHandler',
-      keydown: '_keyDownHandler',
-      keyup: '_keyUpHandler',
+      down: '_downHandler',
+      up: '_upHandler',
       tap: '_tapHandler'
     },
 
+    observers: [
+      '_detectKeyboardFocus(focused)'
+    ],
+
+    keyBindings: {
+      'enter:keydown': '_asyncClick',
+      'space:keydown': '_spaceKeyDownHandler',
+      'space:keyup': '_spaceKeyUpHandler',
+    },
+
     _tapHandler: function() {
       if (this.toggles) {
        // a tap is needed to toggle the active state
         this._userActivate(!this.active);
       } else {
         this.active = false;
       }
     },
 
+    _detectKeyboardFocus: function(focused) {
+      this._setReceivedFocusFromKeyboard(!this.pointerDown && focused);
+    },
+
     // to emulate native checkbox, (de-)activations from a user interaction fire
     // 'change' events
     _userActivate: function(active) {
       this.active = active;
       this.fire('change');
     },
 
     _downHandler: function() {
+      this._setPointerDown(true);
+      this._setPressed(true);
+      this._setReceivedFocusFromKeyboard(false);
+    },
+
+    _upHandler: function() {
+      this._setPointerDown(false);
+      this._setPressed(false);
+    },
+
+    _spaceKeyDownHandler: function(event) {
+      var keyboardEvent = event.detail.keyboardEvent;
+      keyboardEvent.preventDefault();
+      keyboardEvent.stopImmediatePropagation();
       this._setPressed(true);
     },
 
-    _upHandler: function(e) {
+    _spaceKeyUpHandler: function() {
+      if (this.pressed) {
+        this._asyncClick();
+      }
       this._setPressed(false);
     },
 
-    _keyDownHandler: function(e) {
-      switch(e.keyCode) {
-        case this.keyCodes.ENTER_KEY:
-          this._asyncClick();
-          break;
-
-        case this.keyCodes.SPACE:
-          this._setPressed(true);
-          break;
-
-      }
-    },
-
-    _keyUpHandler: function(e) {
-     if (e.keyCode == this.keyCodes.SPACE) {
-        if (this.pressed) {
-          this._asyncClick();
-        }
-        this._setPressed(false);
-      }
-    },
-
     // trigger click asynchronously, the asynchrony is useful to allow one
     // event handler to unwind before triggering another event
     _asyncClick: function() {
       this.async(function() {
         this.click();
       }, 1);
     },
 
     // any of these changes are considered a change to button state
 
     _pressedChanged: function(pressed) {
       this._changedButtonState();
     },
 
     _activeChanged: function(active) {
-      this.setAttribute('aria-pressed', active ? 'true' : 'false');
+      if (this.toggles) {
+        this.setAttribute('aria-pressed', active ? 'true' : 'false');
+      } else {
+        this.removeAttribute('aria-pressed');
+      }
       this._changedButtonState();
     },
 
     _controlStateChanged: function() {
       if (this.disabled) {
         this._setPressed(false);
-        this.active = false;
       } else {
         this._changedButtonState();
       }
     },
 
     // provide hook for follow-on behaviors to react to button-state
 
     _changedButtonState: function() {
       if (this._buttonStateChanged) {
         this._buttonStateChanged(); // abstract
       }
     }
 
   };
 
+  /** @polymerBehavior Polymer.IronButtonState */
+  Polymer.IronButtonState = [
+    Polymer.IronA11yKeysBehavior,
+    Polymer.IronButtonStateImpl
+  ];
+
 </script>