Refactoring NTP5: new implementation of TilePage and MostVisitedPage (which now inherits from Thumb…

chrome/browser/resources/ntp_search/tile_page.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('ntp', function() {
   'use strict';
 
+
+  /**
+   * A virtual Tile class. Each TilePage subclass should have its own Tile
+   * subclass implemented too (e.g. MostVisitedPage contains MostVisited
+   * tiles, and MostVisited is a Tile subclass).
+   * @constructor
+   * @param {Object} gridValues Tile page configuration object.
+   */
+  function Tile(gridValues) {
+    throw 'Tile is a virtual class and is not supposed to be instantiated';
+  }
+
+  /**
+   * Creates a Tile subclass.
+   */
+  Tile.subclass = function(Subclass) {
+    var Base = Tile.prototype;
+    for (var name in Base) {
+      if (!Subclass.hasOwnProperty(name)) {
+        Subclass[name] = Base[name];
+      }
+    }
+    for (var name in TileGetters) {
+      if (!Subclass.hasOwnProperty(name)) {
+        Subclass.__defineGetter__(name, TileGetters[name]);
+      }
+    }
+    return Subclass;
+  };
+
+  Tile.prototype = {
+    initialize: function(gridValues) {
+      // TODO: rename to tile
+      this.baseClassName = 'tile ' + gridValues.tileClassName;
+      this.className = this.baseClassName;
+
+      // TODO set using CSS?
+      if (gridValues.reinforceStyles) {
+        var style = this.style;
+        style.width = gridValues.tileWidth + 'px';
+        style.height = gridValues.tileHeight + 'px';
+        style.borderWidth = gridValues.tileBorderWidth + 'px';
+      }
+    },
+
+    tearDown_: function() {
+    },
+  };
+
+  var TileGetters = {
+    'tileCell': function() {
+      return findAncestorByClass(this, 'tile-cell');
+    },
+    'index': function() {
+      assert(this.tileCell);
+      return this.tileCell.index;
+    }
+  };
+
+
+
   // We can't pass the currently dragging tile via dataTransfer because of
   // http://crbug.com/31037
+  // TODO(xci) drag
   var currentlyDraggingTile = null;
   function getCurrentlyDraggingTile() {
     return currentlyDraggingTile;
   }
   function setCurrentlyDraggingTile(tile) {
     currentlyDraggingTile = tile;
     if (tile)
       ntp.enterRearrangeMode();
     else
       ntp.leaveRearrangeMode();
   }
 
   /**
    * Changes the current dropEffect of a drag. This modifies the native cursor
    * and serves as an indicator of what we should do at the end of the drag as
    * well as give indication to the user if a drop would succeed if they let go.
    * @param {DataTransfer} dataTransfer A dataTransfer object from a drag event.
    * @param {string} effect A drop effect to change to (i.e. copy, move, none).
    */
+  // TODO(xci) drag
   function setCurrentDropEffect(dataTransfer, effect) {
     dataTransfer.dropEffect = effect;
     if (currentlyDraggingTile)
       currentlyDraggingTile.lastDropEffect = dataTransfer.dropEffect;
   }
 
   /**
-   * Creates a new Tile object. Tiles wrap content on a TilePage, providing
-   * some styling and drag functionality.
+   * Creates a new TileCell object. A TileCell represents a cell in the
+   * TilePage's grid. A TilePage uses TileCells to position Tiles in the proper
+   * place and to animate them individually. Each TileCell is associated to
+   * one Tile at a time (or none if it is a filler object), and that association
+   * might change when the grid is resized. When that happens, the grid is
+   * updated and the Tiles are moved to the proper TileCell. We cannot move the
+   * the TileCell itself during the resize because this transition is animated
+   * with CSS and there's no way to stop CSS animations, and we really want to
+   * animate with CSS to take advantage of hardware acceleration.
    * @constructor
    * @extends {HTMLDivElement}
+   * @param {HTMLElement} tile Tile element that will be associated to the cell.
+   * @param {Object} gridValues Tile page configuration object.
    */
-  function Tile(contents) {
-    var tile = cr.doc.createElement('div');
-    tile.__proto__ = Tile.prototype;
-    tile.initialize(contents);
+  function TileCell(tile, gridValues) {
+    var tileCell = cr.doc.createElement('div');
+    tileCell.__proto__ = TileCell.prototype;
+    tileCell.initialize(tile, gridValues);
 
-    return tile;
+    return tileCell;
   }
 
-  Tile.prototype = {
+  TileCell.prototype = {
     __proto__: HTMLDivElement.prototype,
 
-    initialize: function(contents) {
+    initialize: function(tile, gridValues) {
       // 'real' as opposed to doppleganger.
-      this.className = 'tile real';
-      this.appendChild(contents);
-      contents.tile = this;
+      // TODO(xci) remove the real class.
+      this.className = 'tile-cell real';
 
-      this.addEventListener('dragstart', this.onDragStart_);
-      this.addEventListener('drag', this.onDragMove_);
-      this.addEventListener('dragend', this.onDragEnd_);
+      if (gridValues.reinforceStyles) {
+        var style = this.style;
+        var borderWidth = 2 * gridValues.tileBorderWidth;
+        style.width = gridValues.tileWidth + borderWidth + 'px';
+        style.height = gridValues.tileHeight + borderWidth + 'px';
+        // TODO(xci): should we change to marginRight for RTL languages?
+        style.marginLeft = gridValues.tileHorMargin + 'px';
+        style.marginBottom = gridValues.tileVerMargin + 'px';
+      }
 
-      this.firstChild.addEventListener(
-          'webkitAnimationEnd', this.onContentsAnimationEnd_.bind(this));
-
-      this.eventTracker = new EventTracker();
+      this.assign_(tile);
     },
 
     get index() {
-      return Array.prototype.indexOf.call(this.tilePage.tileElements_, this);
+      return Array.prototype.indexOf.call(this.tilePage.tileElements_,
+          this.firstChild);
     },
 
     get tilePage() {
       return findAncestorByClass(this, 'tile-page');
     },
 
-    /**
-     * Position the tile at |x, y|, and store this as the grid location, i.e.
-     * where the tile 'belongs' when it's not being dragged.
-     * @param {number} x The x coordinate, in pixels.
-     * @param {number} y The y coordinate, in pixels.
-     */
-    setGridPosition: function(x, y) {
-      this.gridX = x;
-      this.gridY = y;
-      this.moveTo(x, y);
+    assign_: function(tile) {
+      if (this.firstChild) {
+        this.replaceChild(tile, this.firstChild);
+      } else {
+        this.appendChild(tile);
+      }
+    },
+
+    tearDown_: function() {
     },
 
     /**
-     * Position the tile at |x, y|.
-     * @param {number} x The x coordinate, in pixels.
-     * @param {number} y The y coordinate, in pixels.
-     */
-    moveTo: function(x, y) {
-      // left overrides right in LTR, and right takes precedence in RTL.
-      this.style.left = toCssPx(x);
-      this.style.right = toCssPx(x);
-      this.style.top = toCssPx(y);
-    },
-
-    /**
      * The handler for dragstart events fired on |this|.
      * @param {Event} e The event for the drag.
      * @private
      */
+    // TODO(xci) drag
     onDragStart_: function(e) {
       // The user may start dragging again during a previous drag's finishing
       // animation.
       if (this.classList.contains('dragging'))
         this.finalizeDrag_();
 
       setCurrentlyDraggingTile(this);
 
       e.dataTransfer.effectAllowed = 'copyMove';
       this.firstChild.setDragData(e.dataTransfer);
@@ skipping 19 matching lines @@
           this.parentNode.getBoundingClientRect().top;
 
       this.onDragMove_(e);
     },
 
     /**
      * The handler for drag events fired on |this|.
      * @param {Event} e The event for the drag.
      * @private
      */
+    // TODO(xci) drag
     onDragMove_: function(e) {
       if (e.view != window || (e.x == 0 && e.y == 0)) {
         this.dragClone.hidden = true;
         return;
       }
 
       this.dragClone.hidden = false;
       this.dragClone.style.left = toCssPx(e.x - this.dragOffsetX);
       this.dragClone.style.top = toCssPx(e.y - this.dragOffsetY);
     },
 
     /**
      * The handler for dragend events fired on |this|.
      * @param {Event} e The event for the drag.
      * @private
      */
+    // TODO(xci) drag
     onDragEnd_: function(e) {
       this.dragClone.hidden = false;
       this.dragClone.classList.add('placing');
 
       setCurrentlyDraggingTile(null);
 
       // tilePage will be null if we've already been removed.
       var tilePage = this.tilePage;
       if (tilePage)
-        tilePage.positionTile_(this.index);
+        //tilePage.positionTile_(this.index); // TODO(xci) function was deleted!
 
       // Take an appropriate action with the drag clone.
       if (this.landedOnTrash) {
         this.dragClone.classList.add('deleting');
       } else if (tilePage) {
         // TODO(dbeam): Until we fix dropEffect to the correct behavior it will
         // differ on windows - crbug.com/39399.  That's why we use the custom
         // this.lastDropEffect instead of e.dataTransfer.dropEffect.
         if (tilePage.selected && this.lastDropEffect != 'copy') {
           // The drag clone can still be hidden from the last drag move event.
@@ skipping 32 matching lines @@
       this.landedOnTrash = false;
     },
 
     /**
      * Creates a clone of this node offset by the coordinates. Used for the
      * dragging effect where a tile appears to float off one side of the grid
      * and re-appear on the other.
      * @param {number} x x-axis offset, in pixels.
      * @param {number} y y-axis offset, in pixels.
      */
+    // TODO(xci) drag
     showDoppleganger: function(x, y) {
       // We always have to clear the previous doppleganger to make sure we get
       // style updates for the contents of this tile.
       this.clearDoppleganger();
 
       var clone = this.cloneNode(true);
       clone.classList.remove('real');
       clone.classList.add('doppleganger');
       var clonelets = clone.querySelectorAll('.real');
       for (var i = 0; i < clonelets.length; i++) {
         clonelets[i].classList.remove('real');
       }
 
       this.appendChild(clone);
       this.doppleganger_ = clone;
 
       if (isRTL())
         x *= -1;
 
       this.doppleganger_.style.WebkitTransform = 'translate(' + x + 'px, ' +
                                                                 y + 'px)';
     },
 
     /**
      * Destroys the current doppleganger.
      */
+    // TODO(xci) drag
     clearDoppleganger: function() {
       if (this.doppleganger_) {
         this.removeChild(this.doppleganger_);
         this.doppleganger_ = null;
       }
     },
 
     /**
      * Returns status of doppleganger.
      * @return {boolean} True if there is a doppleganger showing for |this|.
      */
+    // TODO(xci) drag
     hasDoppleganger: function() {
       return !!this.doppleganger_;
     },
 
     /**
      * Cleans up after the drag is over. This is either called when the
      * drag representation finishes animating to the final position, or when
      * the next drag starts (if the user starts a 2nd drag very quickly).
      * @private
      */
+    // TODO(xci) drag
     finalizeDrag_: function() {
       assert(this.classList.contains('dragging'));
 
       var clone = this.dragClone;
       this.dragClone = null;
 
       clone.parentNode.removeChild(clone);
       this.eventTracker.remove(clone, 'webkitTransitionEnd');
       this.classList.remove('dragging');
       if (this.firstChild.finalizeDrag)
         this.firstChild.finalizeDrag();
     },
 
     /**
      * Called when the drag representation node is done migrating to its final
      * resting spot.
      * @param {Event} e The transition end event.
      */
+    // TODO(xci) drag
     onDragCloneTransitionEnd_: function(e) {
       if (this.classList.contains('dragging') &&
           (e.propertyName == 'left' || e.propertyName == 'top' ||
            e.propertyName == '-webkit-transform')) {
         this.finalizeDrag_();
       }
     },
 
     /**
      * Called when an app is removed from Chrome. Animates its disappearance.
@@ skipping 12 matching lines @@
      */
     onContentsAnimationEnd_: function(e) {
       if (this.firstChild.classList.contains('new-tile-contents'))
         this.firstChild.classList.remove('new-tile-contents');
       if (this.firstChild.classList.contains('removing-tile-contents'))
         this.tilePage.removeTile(this, true);
     },
   };
 
   /**
-   * Gives the proportion of the row width that is devoted to a single icon.
-   * @param {number} rowTileCount The number of tiles in a row.
-   * @param {number} tileSpacingFraction The proportion of the tile width which
-   *     will be used as spacing between tiles.
-   * @return {number} The ratio between icon width and row width.
-   */
-  function tileWidthFraction(rowTileCount, tileSpacingFraction) {
-    return rowTileCount + (rowTileCount - 1) * tileSpacingFraction;
-  }
-
-  /**
-   * Calculates an assortment of tile-related values for a grid with the
-   * given dimensions.
-   * @param {number} width The pixel width of the grid.
-   * @param {number} numRowTiles The number of tiles in a row.
-   * @param {number} tileSpacingFraction The proportion of the tile width which
-   *     will be used as spacing between tiles.
-   * @return {Object} A mapping of pixel values.
-   */
-  function tileValuesForGrid(width, numRowTiles, tileSpacingFraction) {
-    var tileWidth = width / tileWidthFraction(numRowTiles, tileSpacingFraction);
-    var offsetX = tileWidth * (1 + tileSpacingFraction);
-    var interTileSpacing = offsetX - tileWidth;
-
-    return {
-      tileWidth: tileWidth,
-      offsetX: offsetX,
-      interTileSpacing: interTileSpacing,
-    };
-  }
-
-  // The smallest amount of horizontal blank space to display on the sides when
-  // displaying a wide arrangement. There is an additional 26px of margin from
-  // the tile page padding.
-  var MIN_WIDE_MARGIN = 18;
-
-  /**
    * Creates a new TilePage object. This object contains tiles and controls
    * their layout.
-   * @param {Object} gridValues Pixel values that define the size and layout
-   *     of the tile grid.
    * @constructor
    * @extends {HTMLDivElement}
    */
-  function TilePage(gridValues) {
+  function TilePage() {
     var el = cr.doc.createElement('div');
-    el.gridValues_ = gridValues;
     el.__proto__ = TilePage.prototype;
     el.initialize();
 
     return el;
   }
 
-  /**
-   * Takes a collection of grid layout pixel values and updates them with
-   * additional tiling values that are calculated from TilePage constants.
-   * @param {Object} grid The grid layout pixel values to update.
-   */
-  TilePage.initGridValues = function(grid) {
-    // The amount of space we need to display a narrow grid (all narrow grids
-    // are this size).
-    grid.narrowWidth =
-        grid.minTileWidth * tileWidthFraction(grid.minColCount,
-                                              grid.tileSpacingFraction);
-    // The minimum amount of space we need to display a wide grid.
-    grid.minWideWidth =
-        grid.minTileWidth * tileWidthFraction(grid.maxColCount,
-                                              grid.tileSpacingFraction);
-    // The largest we will ever display a wide grid.
-    grid.maxWideWidth =
-        grid.maxTileWidth * tileWidthFraction(grid.maxColCount,
-                                              grid.tileSpacingFraction);
-    // Tile-related pixel values for the narrow display.
-    grid.narrowTileValues = tileValuesForGrid(grid.narrowWidth,
-                                              grid.minColCount,
-                                              grid.tileSpacingFraction);
-    // Tile-related pixel values for the minimum narrow display.
-    grid.wideTileValues = tileValuesForGrid(grid.minWideWidth,
-                                            grid.maxColCount,
-                                            grid.tileSpacingFraction);
-  };
-
   TilePage.prototype = {
     __proto__: HTMLDivElement.prototype,
 
+    // The grid values should be defined by each TilePage subclass.
+    gridValues_: {
+      tileWidth: 0,
+      tileHeight: 0,
+      tileHorMargin: 0, // TODO margin with CSS / there's no margin in first col
+      tileVerMargin: 0,
+      tileBorderWidth: 0,
+      bottomPanelHorMargin: 0, // TODO it doesn't make sense having this here.
+
+      tileCount: 0, // TODO remove this dependency. rename it to maxTileCount.
+      tileClassName: '',
+      // TODO(pedrosimonetti): document this property? Consider removing it?
+      reinforceStyles: true,
+
+      // debug
+      slowFactor: 1,
+      debug: false
+    },
+
+    get tileElements() {
+      return this.tileElements_;
+    },
+
     initialize: function() {
       this.className = 'tile-page';
 
-      // Div that acts as a custom scrollbar. The scrollbar has to live
-      // outside the content div so it doesn't flicker when scrolling (due to
-      // repainting after the scroll, then repainting again when moved in the
-      // onScroll handler). |scrollbar_| is only aesthetic, and it only
-      // represents the thumb. Actual events are still handled by the invisible
-      // native scrollbars. This div gives us more flexibility with the visuals.
-      this.scrollbar_ = this.ownerDocument.createElement('div');
-      this.scrollbar_.className = 'tile-page-scrollbar';
-      this.scrollbar_.hidden = true;
-      this.appendChild(this.scrollbar_);
-
       // This contains everything but the scrollbar.
       this.content_ = this.ownerDocument.createElement('div');
       this.content_.className = 'tile-page-content';
       this.appendChild(this.content_);
 
-      // Div that sets the vertical position of the tile grid.
-      this.topMargin_ = this.ownerDocument.createElement('div');
-      this.topMargin_.className = 'top-margin';
-      this.content_.appendChild(this.topMargin_);
-
       // Div that holds the tiles.
       this.tileGrid_ = this.ownerDocument.createElement('div');
       this.tileGrid_.className = 'tile-grid';
-      this.tileGrid_.style.minWidth = this.gridValues_.narrowWidth + 'px';
+      // TODO(xci)
+      //this.tileGrid_.style.minWidth = this.gridValues_.narrowWidth + 'px';
       this.content_.appendChild(this.tileGrid_);
 
+      // TODO(xci) new!
+      this.tileGridContent_ = this.ownerDocument.createElement('div');
+      this.tileGridContent_.className = 'tile-grid-content';
+      this.tileGrid_.appendChild(this.tileGridContent_);
+
+      // TODO(xci) new!
+      this.tileGrid_.addEventListener('webkitTransitionEnd',
+          this.onTileGridAnimationEnd_.bind(this));
+
       // Ordered list of our tiles.
-      this.tileElements_ = this.tileGrid_.getElementsByClassName('tile real');
+      //this.tileElements_ = this.tileGrid_.getElementsByClassName('tile real');
+      this.tileElements_ = [];
+
       // Ordered list of the elements which want to accept keyboard focus. These
       // elements will not be a part of the normal tab order; the tile grid
       // initially gets focused and then these elements can be focused via the
       // arrow keys.
+      // TODO(xci)
+      /*
       this.focusableElements_ =
           this.tileGrid_.getElementsByClassName('focusable');
-
-      // These are properties used in updateTopMargin.
-      this.animatedTopMarginPx_ = 0;
-      this.topMarginPx_ = 0;
+      */
 
       this.eventTracker = new EventTracker();
       this.eventTracker.add(window, 'resize', this.onResize_.bind(this));
+      // TODO(xci) new
+      this.eventTracker.add(window, 'keyup', this.onKeyUp_.bind(this));
 
-      this.addEventListener('DOMNodeInsertedIntoDocument',
-                            this.onNodeInsertedIntoDocument_);
+      // TODO(xci)
+      //this.addEventListener('DOMNodeInsertedIntoDocument',
+      //                      this.onNodeInsertedIntoDocument_);
 
-      this.content_.addEventListener('scroll', this.onScroll_.bind(this));
-
-      this.dragWrapper_ = new cr.ui.DragWrapper(this.tileGrid_, this);
+      //this.dragWrapper_ = new cr.ui.DragWrapper(this.tileGrid_, this);
 
       this.addEventListener('cardselected', this.handleCardSelection_);
       this.addEventListener('carddeselected', this.handleCardDeselection_);
-      this.addEventListener('focus', this.handleFocus_);
-      this.addEventListener('keydown', this.handleKeyDown_);
-      this.addEventListener('mousedown', this.handleMouseDown_);
+      //this.addEventListener('focus', this.handleFocus_);
+      //this.addEventListener('keydown', this.handleKeyDown_);
+      //this.addEventListener('mousedown', this.handleMouseDown_);
 
-      this.focusElementIndex_ = -1;
+      //this.focusElementIndex_ = -1;
     },
 
     get tiles() {
       return this.tileElements_;
     },
 
     get tileCount() {
       return this.tileElements_.length;
     },
 
     get selected() {
       return Array.prototype.indexOf.call(this.parentNode.children, this) ==
           ntp.getCardSlider().currentCard;
     },
 
     /**
-     * The size of the margin (unused space) on the sides of the tile grid, in
-     * pixels.
-     * @type {number}
-     */
-    get sideMargin() {
-      return this.layoutValues_.leftMargin;
-    },
-
-    /**
-     * Returns the width of the scrollbar, in pixels, if it is active, or 0
-     * otherwise.
-     * @type {number}
-     */
-    get scrollbarWidth() {
-      return this.scrollbar_.hidden ? 0 : 13;
-    },
-
-    /**
-     * Returns any extra padding to insert to the bottom of a tile page.  By
-     * default there is none, but subclasses can override.
-     * @type {number}
-     */
-    get extraBottomPadding() {
-      return 0;
-    },
-
-    /**
      * The notification content of this tile (if any, otherwise null).
      * @type {!HTMLElement}
      */
     get notification() {
-      return this.topMargin_.nextElementSibling.id == 'notification-container' ?
-          this.topMargin_.nextElementSibling : null;
+      return this.content_.firstChild.id == 'notification-container' ?
+          this.content_.firstChild : null;
     },
     /**
      * The notification content of this tile (if any, otherwise null).
      * @type {!HTMLElement}
      */
     set notification(node) {
       assert(node instanceof HTMLElement, '|node| isn\'t an HTMLElement!');
       // NOTE: Implicitly removes from DOM if |node| is inside it.
-      this.content_.insertBefore(node, this.topMargin_.nextElementSibling);
+      this.content_.insertBefore(node, this.content_.firstChild);
       this.positionNotification_();
     },
 
     /**
-     * Fetches the size, in pixels, of the padding-top of the tile contents.
-     * @type {number}
-     */
-    get contentPadding() {
-      if (typeof this.contentPadding_ == 'undefined') {
-        this.contentPadding_ =
-            parseInt(getComputedStyle(this.content_).paddingTop, 10);
-      }
-      return this.contentPadding_;
-    },
-
-    /**
      * Removes the tilePage from the DOM and cleans up event handlers.
      */
     remove: function() {
       // This checks arguments.length as most remove functions have a boolean
       // |opt_animate| argument, but that's not necesarilly applicable to
       // removing a tilePage. Selecting a different card in an animated way and
       // deleting the card afterward is probably a better choice.
       assert(typeof arguments[0] != 'boolean',
              'This function takes no |opt_animate| argument.');
       this.tearDown_();
       this.parentNode.removeChild(this);
     },
 
     /**
      * Cleans up resources that are no longer needed after this TilePage
      * instance is removed from the DOM.
      * @private
      */
     tearDown_: function() {
       this.eventTracker.removeAll();
     },
 
     /**
      * Appends a tile to the end of the tile grid.
      * @param {HTMLElement} tileElement The contents of the tile.
      * @param {boolean} animate If true, the append will be animated.
      * @protected
      */
+     // TODO(xci)
+     /*
     appendTile: function(tileElement, animate) {
       this.addTileAt(tileElement, this.tileElements_.length, animate);
     },
+    */
 
     /**
      * Adds the given element to the tile grid.
      * @param {Node} tileElement The tile object/node to insert.
      * @param {number} index The location in the tile grid to insert it at.
      * @param {boolean} animate If true, the tile in question will be
      *     animated (other tiles, if they must reposition, do not animate).
      * @protected
      */
+     // TODO(xci)
+     /*
     addTileAt: function(tileElement, index, animate) {
-      this.classList.remove('animating-tile-page');
-      if (animate)
-        tileElement.classList.add('new-tile-contents');
-
-      // Make sure the index is positive and either in the the bounds of
-      // this.tileElements_ or at the end (meaning append).
-      assert(index >= 0 && index <= this.tileElements_.length);
-
-      var wrapperDiv = new Tile(tileElement);
-      // If is out of the bounds of the tile element list, .insertBefore() will
-      // act just like appendChild().
-      this.tileGrid_.insertBefore(wrapperDiv, this.tileElements_[index]);
       this.calculateLayoutValues_();
-      this.heightChanged_();
-
-      this.repositionTiles_();
       this.fireAddedEvent(wrapperDiv, index, animate);
     },
+    */
 
     /**
      * Notify interested subscribers that a tile has been removed from this
      * page.
-     * @param {Tile} tile The newly added tile.
+     * @param {TileCell} tile The newly added tile.
      * @param {number} index The index of the tile that was added.
      * @param {boolean} wasAnimated Whether the removal was animated.
      */
     fireAddedEvent: function(tile, index, wasAnimated) {
       var e = document.createEvent('Event');
       e.initEvent('tilePage:tile_added', true, true);
       e.addedIndex = index;
       e.addedTile = tile;
       e.wasAnimated = wasAnimated;
       this.dispatchEvent(e);
@@ skipping 13 matching lines @@
       this.calculateLayoutValues_();
       this.cleanupDrag();
 
       if (!opt_dontNotify)
         this.fireRemovedEvent(tile, index, !!opt_animate);
     },
 
     /**
      * Notify interested subscribers that a tile has been removed from this
      * page.
-     * @param {Tile} tile The tile that was removed.
+     * @param {TileCell} tile The tile that was removed.
      * @param {number} oldIndex Where the tile was positioned before removal.
      * @param {boolean} wasAnimated Whether the removal was animated.
      */
     fireRemovedEvent: function(tile, oldIndex, wasAnimated) {
       var e = document.createEvent('Event');
       e.initEvent('tilePage:tile_removed', true, true);
       e.removedIndex = oldIndex;
       e.removedTile = tile;
       e.wasAnimated = wasAnimated;
       this.dispatchEvent(e);
     },
 
     /**
      * Removes all tiles from the page.
      */
     removeAllTiles: function() {
+      // TODO(xci) dispatch individual tearDown functions
       this.tileGrid_.innerHTML = '';
     },
 
     /**
      * Called when the page is selected (in the card selector).
      * @param {Event} e A custom cardselected event.
      * @private
      */
     handleCardSelection_: function(e) {
       this.tabIndex = 1;
@@ skipping 128 matching lines @@
     },
 
     /**
      * Makes some calculations for tile layout. These change depending on
      * height, width, and the number of tiles.
      * TODO(estade): optimize calls to this function. Do nothing if the page is
      * hidden, but call before being shown.
      * @private
      */
     calculateLayoutValues_: function() {
-      var grid = this.gridValues_;
-      var availableSpace = this.tileGrid_.clientWidth - 2 * MIN_WIDE_MARGIN;
-      var wide = availableSpace >= grid.minWideWidth;
-      var numRowTiles = wide ? grid.maxColCount : grid.minColCount;
-
-      var effectiveGridWidth = wide ?
-          Math.min(Math.max(availableSpace, grid.minWideWidth),
-                   grid.maxWideWidth) :
-          grid.narrowWidth;
-      var realTileValues = tileValuesForGrid(effectiveGridWidth, numRowTiles,
-                                             grid.tileSpacingFraction);
-
-      // leftMargin centers the grid within the avaiable space.
-      var minMargin = wide ? MIN_WIDE_MARGIN : 0;
-      var leftMargin =
-          Math.max(minMargin,
-                   (this.tileGrid_.clientWidth - effectiveGridWidth) / 2);
-
-      var rowHeight = this.heightForWidth(realTileValues.tileWidth) +
-          realTileValues.interTileSpacing;
-
-      this.layoutValues_ = {
-        colWidth: realTileValues.offsetX,
-        gridWidth: effectiveGridWidth,
-        leftMargin: leftMargin,
-        numRowTiles: numRowTiles,
-        rowHeight: rowHeight,
-        tileWidth: realTileValues.tileWidth,
-        wide: wide,
-      };
+      this.layout_();
 
       // We need to update the top margin as well.
       this.updateTopMargin_();
 
+      // TODO(pedrosimonetti): when do we really need to send this message?
       this.firePageLayoutEvent_();
     },
 
     /**
      * Dispatches the custom pagelayout event.
      * @private
      */
     firePageLayoutEvent_: function() {
       cr.dispatchSimpleEvent(this, 'pagelayout', true, true);
     },
 
-    /**
-     * @return {number} The amount of margin that should be animated (in pixels)
-     *     for the current grid layout.
-     */
-    getAnimatedLeftMargin_: function() {
-      if (this.layoutValues_.wide)
-        return 0;
-
-      var grid = this.gridValues_;
-      return (grid.minWideWidth - MIN_WIDE_MARGIN - grid.narrowWidth) / 2;
-    },
-
-    /**
-     * Calculates the x/y coordinates for an element and moves it there.
-     * @param {number} index The index of the element to be positioned.
-     * @param {number} indexOffset If provided, this is added to |index| when
-     *     positioning the tile. The effect is that the tile will be positioned
-     *     in a non-default location.
-     * @private
-     */
-    positionTile_: function(index, indexOffset) {
-      var grid = this.gridValues_;
-      var layout = this.layoutValues_;
-
-      indexOffset = typeof indexOffset != 'undefined' ? indexOffset : 0;
-      // Add the offset _after_ the modulus division. We might want to show the
-      // tile off the side of the grid.
-      var col = index % layout.numRowTiles + indexOffset;
-      var row = Math.floor(index / layout.numRowTiles);
-      // Calculate the final on-screen position for the tile.
-      var realX = col * layout.colWidth + layout.leftMargin;
-      var realY = row * layout.rowHeight;
-
-      // Calculate the portion of the tile's position that should be animated.
-      var animatedTileValues = layout.wide ?
-          grid.wideTileValues : grid.narrowTileValues;
-      // Animate the difference between three-wide and six-wide.
-      var animatedLeftMargin = this.getAnimatedLeftMargin_();
-      var animatedX = col * animatedTileValues.offsetX + animatedLeftMargin;
-      var animatedY = row * (this.heightForWidth(animatedTileValues.tileWidth) +
-                             animatedTileValues.interTileSpacing);
-
-      var tile = this.tileElements_[index];
-      tile.setGridPosition(animatedX, animatedY);
-      tile.firstChild.setBounds(layout.tileWidth,
-                                realX - animatedX,
-                                realY - animatedY);
-
-      // This code calculates whether the tile needs to show a clone of itself
-      // wrapped around the other side of the tile grid.
-      var offTheRight = col == layout.numRowTiles ||
-          (col == layout.numRowTiles - 1 && tile.hasDoppleganger());
-      var offTheLeft = col == -1 || (col == 0 && tile.hasDoppleganger());
-      if (this.isCurrentDragTarget && (offTheRight || offTheLeft)) {
-        var sign = offTheRight ? 1 : -1;
-        tile.showDoppleganger(-layout.numRowTiles * layout.colWidth * sign,
-                              layout.rowHeight * sign);
-      } else {
-        tile.clearDoppleganger();
-      }
-
-      if (index == this.tileElements_.length - 1) {
-        this.tileGrid_.style.height = (realY + layout.rowHeight) + 'px';
-        this.queueUpdateScrollbars_();
-      }
-    },
 
     /**
      * Gets the index of the tile that should occupy coordinate (x, y). Note
      * that this function doesn't care where the tiles actually are, and will
      * return an index even for the space between two tiles. This function is
      * effectively the inverse of |positionTile_|.
      * @param {number} x The x coordinate, in pixels, relative to the left of
      *     |this|.
      * @param {number} y The y coordinate, in pixels, relative to the top of
      *     |this|.
      * @private
      */
+    // TODO(xci) drag
     getWouldBeIndexForPoint_: function(x, y) {
       var grid = this.gridValues_;
       var layout = this.layoutValues_;
 
       var gridClientRect = this.tileGrid_.getBoundingClientRect();
       var col = Math.floor((x - gridClientRect.left - layout.leftMargin) /
                            layout.colWidth);
       if (col < 0 || col >= layout.numRowTiles)
         return -1;
 
       if (isRTL())
         col = layout.numRowTiles - 1 - col;
 
       var row = Math.floor((y - gridClientRect.top) / layout.rowHeight);
       return row * layout.numRowTiles + col;
     },
 
     /**
-     * Window resize event handler. Window resizes may trigger re-layouts.
-     * @param {Object} e The resize event.
-     */
-    onResize_: function(e) {
-      if (this.lastWidth_ == this.clientWidth &&
-          this.lastHeight_ == this.clientHeight) {
-        return;
-      }
-
-      this.calculateLayoutValues_();
-
-      this.lastWidth_ = this.clientWidth;
-      this.lastHeight_ = this.clientHeight;
-      this.classList.add('animating-tile-page');
-      this.heightChanged_();
-
-      this.positionNotification_();
-      this.repositionTiles_();
-    },
-
-    /**
      * The tile grid has an image mask which fades at the edges. We only show
      * the mask when there is an active drag; it obscures doppleganger tiles
      * as they enter or exit the grid.
      * @private
      */
+    // TODO(xci) drag
     updateMask_: function() {
       if (!this.isCurrentDragTarget) {
         this.tileGrid_.style.WebkitMaskBoxImage = '';
         return;
       }
 
       var leftMargin = this.layoutValues_.leftMargin;
       // The fade distance is the space between tiles.
       var fadeDistance = (this.gridValues_.tileSpacingFraction *
           this.layoutValues_.tileWidth);
       fadeDistance = Math.min(leftMargin, fadeDistance);
       // On Skia we don't use any fade because it works very poorly. See
       // http://crbug.com/99373
       if (!cr.isMac)
         fadeDistance = 1;
       var gradient =
           '-webkit-linear-gradient(left,' +
               'transparent, ' +
               'transparent ' + (leftMargin - fadeDistance) + 'px, ' +
               'black ' + leftMargin + 'px, ' +
               'black ' + (this.tileGrid_.clientWidth - leftMargin) + 'px, ' +
               'transparent ' + (this.tileGrid_.clientWidth - leftMargin +
                                 fadeDistance) + 'px, ' +
               'transparent)';
       this.tileGrid_.style.WebkitMaskBoxImage = gradient;
     },
 
+    // TODO(xci) delete (used by drag and drop)
     updateTopMargin_: function() {
-      var layout = this.layoutValues_;
-
-      // The top margin is set so that the vertical midpoint of the grid will
-      // be 1/3 down the page.
-      var numTiles = this.tileCount +
-          (this.isCurrentDragTarget && !this.withinPageDrag_ ? 1 : 0);
-      var numRows = Math.max(1, Math.ceil(numTiles / layout.numRowTiles));
-      var usedHeight = layout.rowHeight * numRows;
-      var newMargin = document.documentElement.clientHeight / 3 -
-          usedHeight / 3 - this.contentPadding;
-      // The 'height' style attribute of topMargin is non-zero to work around
-      // webkit's collapsing margin behavior, so we have to factor that into
-      // our calculations here.
-      newMargin = Math.max(newMargin, 0) - this.topMargin_.offsetHeight;
-
-      // |newMargin| is the final margin we actually want to show. However,
-      // part of that should be animated and part should not (for the same
-      // reason as with leftMargin). The approach is to consider differences
-      // when the layout changes from wide to narrow or vice versa as
-      // 'animatable'. These differences accumulate in animatedTopMarginPx_,
-      // while topMarginPx_ caches the real (total) margin. Either of these
-      // calculations may come out to be negative, so we use margins as the
-      // css property.
-
-      if (typeof this.topMarginIsForWide_ == 'undefined')
-        this.topMarginIsForWide_ = layout.wide;
-      if (this.topMarginIsForWide_ != layout.wide) {
-        this.animatedTopMarginPx_ += newMargin - this.topMarginPx_;
-        this.topMargin_.style.marginBottom = toCssPx(this.animatedTopMarginPx_);
-      }
-
-      this.topMarginIsForWide_ = layout.wide;
-      this.topMarginPx_ = newMargin;
-      this.topMargin_.style.marginTop =
-          toCssPx(this.topMarginPx_ - this.animatedTopMarginPx_);
+      return;
     },
 
     /**
      * Position the notification if there's one showing.
      */
     positionNotification_: function() {
-      var notification = this.notification;
-      if (!notification || notification.hidden)
+      if (this.notification && !this.notification.hidden) {
         return;
-
-      // Update the horizontal position.
-      var animatedLeftMargin = this.getAnimatedLeftMargin_();
-      notification.style.WebkitMarginStart = animatedLeftMargin + 'px';
-      var leftOffset = (this.layoutValues_.leftMargin - animatedLeftMargin) *
-                       (isRTL() ? -1 : 1);
-      notification.style.WebkitTransform = 'translateX(' + leftOffset + 'px)';
-
-      // Update the allowable widths of the text.
-      var buttonWidth = notification.querySelector('button').offsetWidth + 8;
-      notification.querySelector('span').style.maxWidth =
-          this.layoutValues_.gridWidth - buttonWidth + 'px';
-
-      // This makes sure the text doesn't condense smaller than the narrow size
-      // of the grid (e.g. when a user makes the window really small).
-      notification.style.minWidth =
-          this.gridValues_.narrowWidth - buttonWidth + 'px';
-
-      // Update the top position.
-      notification.style.marginTop = -notification.offsetHeight + 'px';
+        this.notification.style.margin =
+            -this.notification.offsetHeight + 'px ' +
+            this.layoutValues_.leftMargin + 'px 0';
+      }
     },
 
     /**
      * Handles final setup that can only happen after |this| is inserted into
      * the page.
      * @private
      */
     onNodeInsertedIntoDocument_: function(e) {
       this.calculateLayoutValues_();
-      this.heightChanged_();
-    },
-
-    /**
-     * Called when the height of |this| has changed: update the size of
-     * tileGrid.
-     * @private
-     */
-    heightChanged_: function() {
-      // The tile grid will expand to the bottom footer, or enough to hold all
-      // the tiles, whichever is greater. It would be nicer if tilePage were
-      // a flex box, and the tile grid could be box-flex: 1, but this exposes a
-      // bug where repositioning tiles will cause the scroll position to reset.
-      this.tileGrid_.style.minHeight = (this.clientHeight -
-          this.tileGrid_.offsetTop - this.content_.offsetTop -
-          this.extraBottomPadding -
-          (this.footerNode_ ? this.footerNode_.clientHeight : 0)) + 'px';
     },
 
      /**
       * Places an element at the bottom of the content div. Used in bare-minimum
       * mode to hold #footer.
       * @param {HTMLElement} footerNode The node to append to content.
       */
     appendFooter: function(footerNode) {
       this.footerNode_ = footerNode;
       this.content_.appendChild(footerNode);
@@ skipping 10 matching lines @@
      * @param {Event} e The mousewheel event.
      */
     handleMouseWheel: function(e) {
       if (e.wheelDeltaY == 0)
         return false;
 
       this.content_.scrollTop -= e.wheelDeltaY / 3;
       return true;
     },
 
-    /**
-     * Handler for the 'scroll' event on |content_|.
-     * @param {Event} e The scroll event.
-     * @private
-     */
-    onScroll_: function(e) {
-      this.queueUpdateScrollbars_();
-    },
-
-    /**
-     * ID of scrollbar update timer. If 0, there's no scrollbar re-calc queued.
-     * @private
-     */
-    scrollbarUpdate_: 0,
-
-    /**
-     * Queues an update on the custom scrollbar. Used for two reasons: first,
-     * coalescing of multiple updates, and second, because action like
-     * repositioning a tile can require a delay before they affect values
-     * like clientHeight.
-     * @private
-     */
-    queueUpdateScrollbars_: function() {
-      if (this.scrollbarUpdate_)
-        return;
-
-      this.scrollbarUpdate_ = window.setTimeout(
-          this.doUpdateScrollbars_.bind(this), 0);
-    },
-
-    /**
-     * Does the work of calculating the visibility, height and position of the
-     * scrollbar thumb (there is no track or buttons).
-     * @private
-     */
-    doUpdateScrollbars_: function() {
-      this.scrollbarUpdate_ = 0;
-
-      var content = this.content_;
-
-      // Adjust scroll-height to account for possible header-bar.
-      var adjustedScrollHeight = content.scrollHeight - content.offsetTop;
-
-      if (adjustedScrollHeight <= content.clientHeight) {
-        this.scrollbar_.hidden = true;
-        return;
-      } else {
-        this.scrollbar_.hidden = false;
-      }
-
-      var thumbTop = content.offsetTop +
-          content.scrollTop / adjustedScrollHeight * content.clientHeight;
-      var thumbHeight = content.clientHeight / adjustedScrollHeight *
-          this.clientHeight;
-
-      this.scrollbar_.style.top = thumbTop + 'px';
-      this.scrollbar_.style.height = thumbHeight + 'px';
-      this.firePageLayoutEvent_();
-    },
-
-    /**
-     * Get the height for a tile of a certain width. Override this function to
-     * get non-square tiles.
-     * @param {number} width The pixel width of a tile.
-     * @return {number} The height for |width|.
-     */
-    heightForWidth: function(width) {
-      return width;
-    },
-
     /** Dragging **/
 
+    // TODO(xci) drag
     get isCurrentDragTarget() {
       return this.dragWrapper_.isCurrentDragTarget;
     },
 
     /**
      * Thunk for dragleave events fired on |tileGrid_|.
      * @param {Event} e A MouseEvent for the drag.
      */
+    // TODO(xci) drag
     doDragLeave: function(e) {
       this.cleanupDrag();
     },
 
     /**
      * Performs all actions necessary when a drag enters the tile page.
      * @param {Event} e A mouseover event for the drag enter.
      */
+    // TODO(xci) drag
     doDragEnter: function(e) {
       // Applies the mask so doppleganger tiles disappear into the fog.
       this.updateMask_();
 
       this.classList.add('animating-tile-page');
       this.withinPageDrag_ = this.contains(currentlyDraggingTile);
       this.dragItemIndex_ = this.withinPageDrag_ ?
           currentlyDraggingTile.index : this.tileElements_.length;
       this.currentDropIndex_ = this.dragItemIndex_;
 
       // The new tile may change the number of rows, hence the top margin
       // will change.
       if (!this.withinPageDrag_)
+        // TODO(xci) this function does nothing now!
         this.updateTopMargin_();
 
       this.doDragOver(e);
     },
 
     /**
      * Performs all actions necessary when the user moves the cursor during
      * a drag over the tile page.
      * @param {Event} e A mouseover event for the drag over.
      */
+    // TODO(xci) drag
     doDragOver: function(e) {
       e.preventDefault();
 
       this.setDropEffect(e.dataTransfer);
       var newDragIndex = this.getWouldBeIndexForPoint_(e.pageX, e.pageY);
       if (newDragIndex < 0 || newDragIndex >= this.tileElements_.length)
         newDragIndex = this.dragItemIndex_;
       this.updateDropIndicator_(newDragIndex);
     },
 
     /**
      * Performs all actions necessary when the user completes a drop.
      * @param {Event} e A mouseover event for the drag drop.
      */
+    // TODO(xci) drag
     doDrop: function(e) {
       e.stopPropagation();
       e.preventDefault();
 
       var index = this.currentDropIndex_;
       // Only change data if this was not a 'null drag'.
       if (!((index == this.dragItemIndex_) && this.withinPageDrag_)) {
         var adjustedIndex = this.currentDropIndex_ +
             (index > this.dragItemIndex_ ? 1 : 0);
         if (this.withinPageDrag_) {
@@ skipping 16 matching lines @@
       }
 
       this.classList.remove('animating-tile-page');
       this.cleanupDrag();
     },
 
     /**
      * Appends the currently dragged tile to the end of the page. Called
      * from outside the page, e.g. when dropping on a nav dot.
      */
+    // TODO(xci) drag
     appendDraggingTile: function() {
       var originalPage = currentlyDraggingTile.tilePage;
       if (originalPage == this)
         return;
 
       this.addDragData(null, this.tileElements_.length);
       if (originalPage)
         originalPage.cleanupDrag();
     },
 
     /**
      * Makes sure all the tiles are in the right place after a drag is over.
      */
+    // TODO(xci) drag
     cleanupDrag: function() {
       this.repositionTiles_(currentlyDraggingTile);
       // Remove the drag mask.
       this.updateMask_();
     },
 
     /**
      * Reposition all the tiles (possibly ignoring one).
      * @param {?Node} ignoreNode An optional node to ignore.
      * @private
      */
+    // TODO(xci) drag
     repositionTiles_: function(ignoreNode) {
+      /*
       for (var i = 0; i < this.tileElements_.length; i++) {
         if (!ignoreNode || ignoreNode !== this.tileElements_[i])
-          this.positionTile_(i);
+          ;//this.positionTile_(i); TODO(xci) this function was deleted!
       }
+      */
     },
 
     /**
      * Updates the visual indicator for the drop location for the active drag.
      * @param {Event} e A MouseEvent for the drag.
      * @private
      */
+    // TODO(xci) drag
     updateDropIndicator_: function(newDragIndex) {
       var oldDragIndex = this.currentDropIndex_;
       if (newDragIndex == oldDragIndex)
         return;
 
       var repositionStart = Math.min(newDragIndex, oldDragIndex);
       var repositionEnd = Math.max(newDragIndex, oldDragIndex);
 
       for (var i = repositionStart; i <= repositionEnd; i++) {
         if (i == this.dragItemIndex_)
           continue;
         else if (i > this.dragItemIndex_)
           var adjustment = i <= newDragIndex ? -1 : 0;
         else
           var adjustment = i >= newDragIndex ? 1 : 0;
 
-        this.positionTile_(i, adjustment);
+        //this.positionTile_(i, adjustment); TODO(xci) function was deleted!
       }
       this.currentDropIndex_ = newDragIndex;
     },
 
     /**
      * Checks if a page can accept a drag with the given data.
      * @param {Event} e The drag event if the drag object. Implementations will
      *     likely want to check |e.dataTransfer|.
      * @return {boolean} True if this page can handle the drag.
      */
+    // TODO(xci) drag
     shouldAcceptDrag: function(e) {
       return false;
     },
 
     /**
      * Called to accept a drag drop. Will not be called for in-page drops.
      * @param {Object} dataTransfer The data transfer object that holds the drop
      *     data. This should only be used if currentlyDraggingTile is null.
      * @param {number} index The tile index at which the drop occurred.
      */
+    // TODO(xci) drag
     addDragData: function(dataTransfer, index) {
       assert(false);
     },
 
     /**
      * Called when a tile has been moved (via dragging). Override this to make
      * backend updates.
      * @param {Node} draggedTile The tile that was dropped.
      * @param {number} prevIndex The previous index of the tile.
      */
     tileMoved: function(draggedTile, prevIndex) {
     },
 
     /**
      * Sets the drop effect on |dataTransfer| to the desired value (e.g.
      * 'copy').
      * @param {Object} dataTransfer The drag event dataTransfer object.
      */
+    // TODO(xci) drag
     setDropEffect: function(dataTransfer) {
       assert(false);
     },
+
+
+    // #########################################################################
+    // XCI - Extended Chrome Instant
+    // #########################################################################
+
+
+    // properties
+    // -------------------------------------------------------------------------
+    colCount: 5,
+    rowCount: 2,
+
+    numOfVisibleRows: 0,
+    animatingColCount: 5, // TODO how to handle initialization of this value?
+
+    // TODO move to layout?
+    pageOffset: 0,
+
+    appendTile: function(tile) {
+      this.tileElements_.push(tile);
+      this.renderGrid_();
+    },
+
+    // TODO(cxi): if this is not being used, delete.
+    addTileAt: function(tile, index) {
+      this.tileElements_.splice(index, 0, tile);
+      this.appendTile(tile);
+    },
+
+    // internal helpers
+    // -------------------------------------------------------------------------
+
+    // TODO move to layout?
+    getNumOfVisibleRows_: function() {
+      return this.numOfVisibleRows;
+    },
+
+    getTileRequiredWidth_: function() {
+      var grid = this.gridValues_;
+      return grid.tileWidth + 2 * grid.tileBorderWidth + grid.tileHorMargin;
+    },
+
+    getColCountForWidth_: function(width) {
+      var availableWidth = width + this.gridValues_.tileHorMargin;
+      var requiredWidth = this.getTileRequiredWidth_();
+      var colCount = Math.floor(availableWidth / requiredWidth);
+      return colCount;
+    },
+
+    getWidthForColCount_: function(colCount) {
+      var requiredWidth = this.getTileRequiredWidth_();
+      var width = colCount * requiredWidth - this.gridValues_.tileHorMargin;
+      return width;
+    },
+
+    getBottomPanelWidth_: function() {
+      var windowWidth = cr.doc.documentElement.clientWidth;
+      var width;
+      // TODO(xci): add contants?
+      if (windowWidth >= 948) {
+        width = 748;
+      } else if (windowWidth >= 500) {
+        width = windowWidth - 2 * this.gridValues_.bottomPanelHorMargin;
+      } else if (windowWidth >= 300) {
+        // TODO(pedrosimonetti): check math and document
+        width = Math.floor(((windowWidth - 300) / 200) * 100 + 200);
+      } else {
+        width = 200;
+      }
+      return width;
+    },
+
+    getAvailableColCount_: function() {
+      return this.getColCountForWidth_(this.getBottomPanelWidth_());
+    },
+
+    // rendering
+    // -------------------------------------------------------------------------
+
+    // TODO(pedrosimonetti): document
+    renderGrid_: function(colCount) {
+      colCount = colCount || this.colCount;
+
+      var tileGridContent = this.tileGridContent_;
+
+      var tileElements = this.tileElements_;
+
+      var tileCount = tileElements.length;
+      var rowCount = Math.ceil(tileCount / colCount);
+
+      var tileRows = tileGridContent.getElementsByClassName('tile-row');
+      var tileRow;
+      var tileRowTiles;
+      var tileCell;
+      var tileElement;
+      var maxColCount;
+
+      var numOfVisibleRows = this.getNumOfVisibleRows_();
+      var pageOffset = this.pageOffset;
+
+      for (var tile = 0, row = 0; row < rowCount; row++) {
+        tileRow = tileRows[row];
+
+        // Create tile row if there's no one yet.
+        if (!tileRow) {
+          tileRow = cr.doc.createElement('div');
+          tileRow.className = 'tile-row tile-row-' + row;// TODO do we need id?
+          tileGridContent.appendChild(tileRow);
+        }
+
+        // Adjust row visibility.
+        var rowVisible = (row >= pageOffset &&
+            row <= (pageOffset + numOfVisibleRows - 1));
+        this.showTileRow_(tileRow, rowVisible);
+
+        // The tiles inside the current row.
+        tileRowTiles = tileRow.childNodes;
+
+        // Remove excessive columns from a particular tile row.
+        maxColCount = Math.min(colCount, tileCount - tile);
+        while (tileRowTiles.length > maxColCount) {
+          tileRow.removeChild(tileRow.lastElementChild);
+        }
+
+        // For each column in the current row.
+        for (var col = 0; col < colCount; col++, tile++) {
+          if (tileRowTiles[col]) {
+            tileCell = tileRowTiles[col];
+          } else {
+            var span = cr.doc.createElement('span');
+            tileCell = new TileCell(span, this.gridValues_);
+          }
+
+          // Reset column class.
+          this.resetTileCol_(tileCell, col);
+
+          // Render Tiles.
+          if (tile < tileCount) {
+            tileCell.classList.remove('filler');
+            tileElement = tileElements[tile];
+            if (tileCell.firstChild) {
+              if (tileElement != tileCell.firstChild) {
+                tileCell.replaceChild(tileElement, tileCell.firstChild);
+              }
+            } else {
+              tileCell.appendChild(tileElement);
+            }
+          } else {
+            // TODO(xci): check how to solve the problem with filler + animation
+            if (!tileCell.classList.contains('filler')) {
+              tileCell.classList.add('filler');
+              tileElement = cr.doc.createElement('span');
+              if (tileCell.firstChild)
+                tileCell.replaceChild(tileElement, tileCell.firstChild);
+              else
+                tileCell.appendChild(tileElement);
+            }
+          }
+
+          if (!tileRowTiles[col]) {
+            tileRow.appendChild(tileCell);
+          }
+        }
+      }
+
+      // Remove excessive tile rows from the tile grid.
+      while (tileRows.length > rowCount) {
+        tileGridContent.removeChild(tileGridContent.lastElementChild);
+      }
+
+      this.colCount = colCount;
+      this.rowCount = rowCount;
+    },
+
+    layout_: function() {
+      var pageList = $('page-list');
+      var panel = this.content_;
+      var menu = $('page-list-menu');
+      var tileGrid = this.tileGrid_;
+      var tileGridContent = this.tileGridContent_;
+      var tileRows = tileGridContent.getElementsByClassName('tile-row');
+
+      tileGridContent.classList.add('animate-tile');
+
+      var bottomPanelWidth = this.getBottomPanelWidth_();
+      var colCount = this.getColCountForWidth_(bottomPanelWidth);
+      var lastColCount = this.colCount;
+      var animatingColCount = this.animatingColCount;
+
+      var windowHeight = cr.doc.documentElement.clientHeight;
+
+      // TODO better handling of height state
+      // changeVisibleRows
+      // TODO need to call paginate when height changes
+      var numOfVisibleRows = this.numOfVisibleRows;
+      // TODO(xci) constants?
+      if (windowHeight > 500 && this.tileElements_.length > 5) {
+        numOfVisibleRows = 2;
+      } else {
+        numOfVisibleRows = 1;
+      }
+
+      if (numOfVisibleRows != this.numOfVisibleRows) {
+        this.numOfVisibleRows = numOfVisibleRows;
+        this.paginate_(null, true);
+        pageList.style.height = (107 * numOfVisibleRows) + 'px';
+        //tileGrid.style.height = (107 * numOfVisibleRows) + 'px';
+      }
+
+      // changeVisibleCols
+      if (colCount != animatingColCount) {
+
+        var newWidth = this.getWidthForColCount_(colCount);
+        if (colCount > animatingColCount) {
+
+          // TODO actual size check
+          if (colCount != lastColCount) {
+            this.renderGrid_(colCount);
+          }
+
+          this.showTileCols_(animatingColCount, false);
+
+          // TODO(xci) fix the slowdown debug function and test if we really
+          // need this closure and if we really need to pass animatingCount.
+          var self = this;
+          setTimeout((function(animatingColCount) {
+            return function() {
+              self.showTileCols_(animatingColCount, true);
+            }
+          })(animatingColCount), 0);
+
+        } else {
+          this.showTileCols_(colCount, false);
+        }
+
+        tileGrid.style.width = newWidth + 'px';
+        menu.style.width = newWidth + 'px';
+
+        // TODO: listen animateEnd
+        var self = this;
+        this.onTileGridAnimationEndHandler_ = function() {
+          if (colCount < lastColCount) {
+            self.renderGrid_(colCount);
+          } else {
+            self.showTileCols_(0, true);
+          }
+        };
+
+        this.paginate_();
+      }
+
+      panel.style.width = bottomPanelWidth + 'px';
+
+      this.animatingColCount = colCount;
+    },
+
+    // animation helpers
+    // -------------------------------------------------------------------------
+
+    // TODO make it local?
+    showTileRow_: function(row, show) {
+      row.classList[show ? 'remove' : 'add']('hide-row');
+    },
+
+    // TODO make it local?
+    showTileCols_: function(col, show) {
+      var prop = show ? 'remove' : 'add';
+      var max = 10; // TODO(pedrosimonetti) const?
+      var tileGridContent = this.tileGridContent_;
+      for (var i = col; i < max; i++) {
+        tileGridContent.classList[prop]('hide-col-' + i);
+      }
+    },
+
+    // TODO make it local?
+    resetTileCol_: function(tileCell, col) {
+      var max = 10;
+      for (var i = 0; i < max; i++) {
+        if (i != col) {
+          tileCell.classList.remove('tile-col-' + i);
+        }
+      }
+      tileCell.classList.add('tile-col-' + col);
+    },
+
+    // pagination
+    // -------------------------------------------------------------------------
+
+    paginate_: function(pageOffset, force) {
+      var numOfVisibleRows = this.getNumOfVisibleRows_();
+      var pageOffset = typeof pageOffset == 'number' ?
+          pageOffset : this.pageOffset;
+
+      pageOffset = Math.max(0, pageOffset);
+      pageOffset = Math.min(this.rowCount - numOfVisibleRows, pageOffset);
+
+      if (pageOffset != this.pageOffset || force) {
+        var rows = this.tileGridContent_.getElementsByClassName('tile-row');
+        for (var i = 0, l = rows.length; i < l; i++) {
+          var row = rows[i];
+          if (i >= pageOffset && i <= (pageOffset + numOfVisibleRows - 1)) {
+            this.showTileRow_(row, true);
+          } else {
+            this.showTileRow_(row, false);
+          }
+        }
+
+        this.pageOffset = pageOffset;
+        this.tileGridContent_.style.webkitTransform = 'translate3d(0, ' +
+            (-pageOffset * 106) + 'px, 0)';
+      }
+    },
+
+    // event handlers
+    // -------------------------------------------------------------------------
+
+    onResize_: function() {
+      this.layout_();
+    },
+
+    onTileGridAnimationEnd_: function() {
+      // TODO(xci): figure out how to cleanup each kind animation properly
+      if (event.target == this.tileGrid_ &&
+          this.onTileGridAnimationEndHandler_) {
+        if (this.tileGridContent_.classList.contains('animate-tile')) {
+          this.onTileGridAnimationEndHandler_();
+          //this.tileGridContent_.classList.remove('animate-tile')
+        }
+      }
+    },
+
+    onKeyUp_: function(e) {
+      var pageOffset = this.pageOffset;
+
+      var keyCode = e.keyCode;
+      if (keyCode == 40 /* down */) {
+        pageOffset++;
+      } else if (keyCode == 38 /* up */) {
+        pageOffset--;
+      }
+
+      if (pageOffset != this.pageOffset) {
+        this.paginate_(pageOffset);
+      }
+    }
   };
 
+
+  var duration = 200;
+  var defaultDuration = 200;
+  var animatedProperties = [
+    '#card-slider-frame .tile-grid',
+    '#card-slider-frame .tile-grid-content',
+    '#card-slider-frame .tile-row',
+    '.animate-tile .tile-cell',
+    '.debug .animate-tile .tile-cell'
+  ];
+
+  function adjustAnimationTiming(slownessFactor, selectors) {
+    slownessFactor = slownessFactor || 1;
+    selectors = selectors || animatedProperties;
+    duration = defaultDuration * slownessFactor;
+    for (var i = 0, l = selectors.length; i < l; i++) {
+      var selector = selectors[i];
+      var rule = findCSSRule(selector);
+      if (rule) {
+        rule.style.webkitTransitionDuration = duration + 'ms';
+      } else {
+        throw 'Could not find the CSS rule "' + selector + '"';
+      }
+    }
+  }
+
+  function findCSSRule(selectorText) {
+    var rules = document.styleSheets[0].rules;
+    for (var i = 0, l = rules.length; i < l; i++) {
+      var rule = rules[i];
+      if (rule.selectorText == selectorText)
+      {
+        return rule;
+      }
+    }
+  }
+
+  function changeSlowFactor(el) {
+    if (el.value)
+      adjustAnimationTiming(el.value - 0, animatedProperties);
+  }
+
+  function changeDebugMode(el) {
+    var prop = el.checked ? 'add' : 'remove';
+    document.body.classList[prop]('debug');
+  }
+
   return {
-    getCurrentlyDraggingTile: getCurrentlyDraggingTile,
-    setCurrentDropEffect: setCurrentDropEffect,
-    TilePage: TilePage,
+    // TODO(xci) drag
+    //getCurrentlyDraggingTile2: getCurrentlyDraggingTile,
+    //setCurrentDropEffect2: setCurrentDropEffect,
+    Tile2: Tile,
+    TilePage2: TilePage,
   };
 });