systrace/catapult/third_party/polymer/components/paper-behaviors/paper-inky-focus-behavior.html

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This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-behaviors/iron-button-state.html">
<link rel="import" href="paper-ripple-behavior.html">

<script>
  /**
   * `Polymer.PaperInkyFocusBehavior` implements a ripple when the element has keyboard focus.
   *
   * @polymerBehavior Polymer.PaperInkyFocusBehavior
   */
  Polymer.PaperInkyFocusBehaviorImpl = {
    observers: [
      '_focusedChanged(receivedFocusFromKeyboard)'
    ],

    _focusedChanged: function(receivedFocusFromKeyboard) {
      if (receivedFocusFromKeyboard) {
        this.ensureRipple();
      }
      if (this.hasRipple()) {
        this._ripple.holdDown = receivedFocusFromKeyboard;
      }
    },

    _createRipple: function() {
      var ripple = Polymer.PaperRippleBehavior._createRipple();
      ripple.id = 'ink';
      ripple.setAttribute('center', '');
      ripple.classList.add('circle');
      return ripple;
    }
  };

  /** @polymerBehavior Polymer.PaperInkyFocusBehavior */
  Polymer.PaperInkyFocusBehavior = [
    Polymer.IronButtonState,
    Polymer.IronControlState,
    Polymer.PaperRippleBehavior,
    Polymer.PaperInkyFocusBehaviorImpl
  ];
</script>