Polymer: Remove unused app-layout element

third_party/polymer/v1_0/components-chromium/app-layout/app-scroll-effects/app-scroll-effects-behavior-extracted.js

-/**
-   * `Polymer.AppScrollEffectsBehavior` provides an interface that allows an element to use scrolls effects.
-   *
-   * ### Importing the app-layout effects
-   *
-   * app-layout provides a set of scroll effects that can be used by explicitly importing
-   * `app-scroll-effects.html`:
-   *
-   * ```html
-   * <link rel="import" href="/bower_components/app-layout/app-scroll-effects/app-scroll-effects.html">
-   * ```
-   *
-   * The scroll effects can also be used by individually importing
-   * `app-layout/app-scroll-effects/effects/[effectName].html`. For example:
-   *
-   * ```html
-   *  <link rel="import" href="/bower_components/app-layout/app-scroll-effects/effects/waterfall.html">
-   * ```
-   *
-   * ### Consuming effects
-   *
-   * Effects can be consumed via the `effects` property. For example:
-   *
-   * ```html
-   * <app-header effects="waterfall"></app-header>
-   * ```
-   *
-   * ### Creating scroll effects
-   *
-   * You may want to create a custom scroll effect if you need to modify the CSS of an element
-   * based on the scroll position.
-   *
-   * A scroll effect definition is an object with `setUp()`, `tearDown()` and `run()` functions.
-   * 
-   * To register the effect, you can use `Polymer.AppLayout.registerEffect(effectName, effectDef)`
-   * For example, let's define an effect that resizes the header's logo:
-   *
-   * ```js
-   * Polymer.AppLayout.registerEffect('resizable-logo', {
-   *   setUp: function(config) {
-   *     // the effect's config is passed to the setUp.
-   *     this._fxResizeLogo = { logo: Polymer.dom(this).querySelector('[logo]') };
-   *   },
-   *
-   *   run: function(progress) {
-   *      // the progress of the effect
-   *      this.transform('scale3d(' + progress + ', '+ progress +', 1)',  this._fxResizeLogo.logo);
-   *   },
-   *
-   *   tearDown: function() {
-   *      // clean up and reset of states
-   *      delete this._fxResizeLogo;
-   *   }
-   * });
-   * ```
-   * Now, you can consume the effect:
-   *
-   * ```html
-   * <app-header id="appHeader" effects="resizable-logo">
-   *   <img logo src="logo.svg">
-   * </app-header>
-   * ```
-   *
-   * ### Imperative API
-   *
-   * ```js
-   * var logoEffect = appHeader.createEffect('resizable-logo', effectConfig);
-   * // run the effect: logoEffect.run(progress);
-   * // tear down the effect: logoEffect.tearDown();
-   * ```
-   *
-   * ### Configuring effects
-   *
-   * For effects installed via the `effects` property, their configuration can be set
-   * via the `effectsConfig` property. For example:
-   *
-   * ```html
-   * <app-header effects="waterfall"
-   *   effects-config='{"waterfall": {"startsAt": 0, "endsAt": 0.5}}'>
-   * </app-header>
-   * ```
-   *
-   * All effects have a `startsAt` and `endsAt` config property. They specify at what
-   * point the effect should start and end. This value goes from 0 to 1 inclusive.
-   *
-   * @polymerBehavior
-   */
-  Polymer.AppScrollEffectsBehavior = [
-    Polymer.IronScrollTargetBehavior,
-   {
-
-    properties: {
-
-      /**
-       * A space-separated list of the effects names that will be triggered when the user scrolls.
-       * e.g. `waterfall parallax-background` installs the `waterfall` and `parallax-background`.
-       */
-      effects: {
-        type: String
-      },
-
-      /**
-       * An object that configurates the effects installed via the `effects` property. e.g.
-       * ```js
-       *  element.effectsConfig = {
-       *   "blend-background": {
-       *     "startsAt": 0.5
-       *   }
-       * };
-       * ```
-       * Every effect has at least two config properties: `startsAt` and `endsAt`.
-       * These properties indicate when the event should start and end respectively
-       * and relative to the overall element progress. So for example, if `blend-background`
-       * starts at `0.5`, the effect will only start once the current element reaches 0.5
-       * of its progress. In this context, the progress is a value in the range of `[0, 1]`
-       * that indicates where this element is on the screen relative to the viewport.
-       */
-      effectsConfig: {
-        type: Object,
-        value: function() {
-          return {};
-        }
-      },
-
-      /**
-       * Disables CSS transitions and scroll effects on the element.
-       */
-      disabled: {
-        type: Boolean,
-        reflectToAttribute: true,
-        value: false
-      }
-    },
-
-    observers: [
-      '_effectsChanged(effects, effectsConfig, isAttached)'
-    ],
-
-    /**
-     * Updates the scroll state. This method should be overridden
-     * by the consumer of this behavior.
-     *
-     * @method _updateScrollState
-     */
-    _updateScrollState: function() {},
-
-    /**
-     * Returns true if the current element is on the screen.
-     * That is, visible in the current viewport. This method should be
-     * overridden by the consumer of this behavior.
-     *
-     * @method isOnScreen
-     * @return {boolean}
-     */
-    isOnScreen: function() {
-      return false;
-    },
-
-    /**
-     * Returns true if there's content below the current element. This method
-     * should be overridden by the consumer of this behavior.
-     *
-     * @method isContentBelow
-     * @return {boolean}
-     */
-    isContentBelow: function() {
-      return false;
-    },
-
-    /**
-     * List of effects handlers that will take place during scroll.
-     *
-     * @type {Array<Function>}
-     */
-    _effectsRunFn: null,
-
-    /**
-     * List of the effects definitions installed via the `effects` property.
-     *
-     * @type {Array<Object>}
-     */
-    _effects: null,
-
-    /**
-     * The clamped value of `_scrollTop`.
-     * @type number
-     */
-    get _clampedScrollTop() {
-      return Math.max(0, this._scrollTop);
-    },
-
-    detached: function() {
-      this._tearDownEffects();
-    },
-
-    /**
-     * Creates an effect object from an effect's name that can be used to run
-     * effects programmatically.
-     *
-     * @method createEffect
-     * @param {string} effectName The effect's name registered via `Polymer.AppLayout.registerEffect`.
-     * @param {Object=} effectConfig The effect config object. (Optional)
-     * @return {Object} An effect object with the following functions:
-     *
-     *  * `effect.setUp()`, Sets up the requirements for the effect.
-     *       This function is called automatically before the `effect` function returns.
-     *  * `effect.run(progress, y)`, Runs the effect given a `progress`.
-     *  * `effect.tearDown()`, Cleans up any DOM nodes or element references used by the effect.
-     *
-     * Example:
-     * ```js
-     * var parallax = element.createEffect('parallax-background');
-     * // runs the effect
-     * parallax.run(0.5, 0);
-     * ```
-     */
-    createEffect: function(effectName, effectConfig) {
-      var effectDef = Polymer.AppLayout._scrollEffects[effectName];
-      if (!effectDef) {
-        throw new ReferenceError(this._getUndefinedMsg(effectName));
-      }
-      var prop = this._boundEffect(effectDef, effectConfig || {});
-      prop.setUp();
-      return prop;
-    },
-
-    /**
-     * Called when `effects` or `effectsConfig` changes.
-     */
-    _effectsChanged: function(effects, effectsConfig, isAttached) {
-      this._tearDownEffects();
-
-      if (effects === '' || !isAttached) {
-        return;
-      }
-      effects.split(' ').forEach(function(effectName) {
-        var effectDef;
-        if (effectName !== '') {
-          if ((effectDef = Polymer.AppLayout._scrollEffects[effectName])) {
-            this._effects.push(this._boundEffect(effectDef, effectsConfig[effectName]));
-          } else {
-            this._warn(this._logf('_effectsChanged', this._getUndefinedMsg(effectName)));
-          }
-        }
-      }, this);
-
-      this._setUpEffect();
-    },
-
-    /**
-     * Forces layout
-     */
-    _layoutIfDirty: function() {
-      return this.offsetWidth;
-    },
-
-    /**
-     * Returns an effect object bound to the current context.
-     *
-     * @param {Object} effectDef
-     * @param {Object=} effectsConfig The effect config object if the effect accepts config values. (Optional)
-     */
-    _boundEffect: function(effectDef, effectsConfig) {
-      effectsConfig = effectsConfig || {};
-      var startsAt = parseFloat(effectsConfig.startsAt || 0);
-      var endsAt = parseFloat(effectsConfig.endsAt || 1);
-      var deltaS = endsAt - startsAt;
-      var noop = Function();
-      // fast path if possible
-      var runFn = (startsAt === 0 && endsAt === 1) ? effectDef.run :
-        function(progress, y) {
-          effectDef.run.call(this,
-              Math.max(0, (progress - startsAt) / deltaS), y);
-        };
-      return {
-        setUp: effectDef.setUp ? effectDef.setUp.bind(this, effectsConfig) : noop,
-        run: effectDef.run ? runFn.bind(this) : noop,
-        tearDown: effectDef.tearDown ? effectDef.tearDown.bind(this) : noop
-      };
-    },
-
-    /**
-     * Sets up the effects.
-     */
-    _setUpEffect: function() {
-      if (this.isAttached && this._effects) {
-        this._effectsRunFn = [];
-        this._effects.forEach(function(effectDef) {
-          // install the effect only if no error was reported
-          if (effectDef.setUp() !== false) {
-            this._effectsRunFn.push(effectDef.run);
-          }
-        }, this);
-      }
-    },
-
-    /**
-     * Tears down the effects.
-     */
-    _tearDownEffects: function() {
-      if (this._effects) {
-        this._effects.forEach(function(effectDef) {
-          effectDef.tearDown();
-        });
-      }
-      this._effectsRunFn = [];
-      this._effects = [];
-    },
-
-    /**
-     * Runs the effects.
-     *
-     * @param {number} p The progress
-     * @param {number} y The top position of the current element relative to the viewport.
-     */
-    _runEffects: function(p, y) {
-      if (this._effectsRunFn) {
-        this._effectsRunFn.forEach(function(run) {
-          run(p, y);
-        });
-      }
-    },
-
-    /**
-     * Overrides the `_scrollHandler`.
-     */
-    _scrollHandler: function() {
-      if (!this.disabled) {
-        this._updateScrollState(this._clampedScrollTop);
-      }
-    },
-    
-    /**
-     * Override this method to return a reference to a node in the local DOM.
-     * The node is consumed by a scroll effect.
-     *
-     * @param {string} id The id for the node.
-     */
-    _getDOMRef: function(id) {
-      this._warn(this._logf('_getDOMRef', '`'+ id +'` is undefined'));
-    },
-
-    _getUndefinedMsg: function(effectName) {
-      return 'Scroll effect `' + effectName + '` is undefined. ' +
-          'Did you forget to import app-layout/app-scroll-effects/effects/' + effectName + '.html ?';
-    }
-
-  }];