Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components-chromium/iron-behaviors/iron-button-state-extracted.js

Index: third_party/polymer/v0_8/components-chromium/iron-behaviors/iron-button-state-extracted.js
diff --git a/third_party/polymer/v0_8/components-chromium/iron-behaviors/iron-button-state-extracted.js b/third_party/polymer/v0_8/components-chromium/iron-behaviors/iron-button-state-extracted.js
new file mode 100644
index 0000000000000000000000000000000000000000..dd8057d25f922e39293a78a0455b1aef3ecf95a5
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+++ b/third_party/polymer/v0_8/components-chromium/iron-behaviors/iron-button-state-extracted.js
@@ -0,0 +1,141 @@
+
+
+  Polymer.IronButtonState = {
+
+    properties: {
+
+      /**
+       * If true, the user is currently holding down the button.
+       *
+       * @attribute pressed
+       * @type boolean
+       * @default false
+       */
+      pressed: {
+        type: Boolean,
+        readOnly: true,
+        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,
+        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,
+        notify: true,
+        reflectToAttribute: true,
+        observer: '_activeChanged'
+      }
+
+    },
+
+    listeners: {
+      mousedown: '_downHandler',
+      mouseup: '_upHandler',
+      keydown: '_keyDownHandler',
+      keyup: '_keyUpHandler',
+      tap: '_tapHandler'
+    },
+
+    _tapHandler: function() {
+      if (this.toggles) {
+       // a tap is needed to toggle the active state
+        this._userActivate(!this.active);
+      } else {
+        this.active = false;
+      }
+    },
+
+    // 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._setPressed(true);
+    },
+
+    _upHandler: function(e) {
+      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');
+      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
+      }
+    }
+
+  };
+