Disable VK overscroll for login/out-of-box.

chrome/browser/resources/login/user_pod_row.js

 // Copyright 2014 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.
 
 /**
  * @fileoverview User pod row implementation.
  */
 
 cr.define('login', function() {
   /**
@@ skipping 29 matching lines @@
    * Variables used for pod placement processing. Width and height should be
    * synced with computed CSS sizes of pods.
    */
   var POD_WIDTH = 180;
   var PUBLIC_EXPANDED_WIDTH = 420;
   var CROS_POD_HEIGHT = 213;
   var DESKTOP_POD_HEIGHT = 216;
   var POD_ROW_PADDING = 10;
 
   /**
+   * Constants that define 'scrolling stops' when user pod rows are scrolled
+   * into view with virtual keyboard shown. First index is total number of rows,
+   * second index is focused pod row. See scrollFocusedPodIntoView().
+   * @type Array.<Array.<number>>
+   * @const
+   */
+  var USER_POD_ROW_SCROLL_STOPS = [[0.5], [0.25, 0.75], [0, 0.5, 1]];

[dzhioev (left Google), 2014/05/21 17:30:32]

We can have more than 3 rows of pods. What happens then?

[Nikita (slow), 2014/05/22 15:11:50]

Added dynamic calculation.

+
+  /**
    * Whether to preselect the first pod automatically on login screen.
    * @type {boolean}
    * @const
    */
   var PRESELECT_FIRST_POD = true;
 
   /**
    * Maximum time for which the pod row remains hidden until all user images
    * have been loaded.
    * @type {number}
@@ skipping 89 matching lines @@
   /**
    * Unique salt added to user image URLs to prevent caching. Dictionary with
    * user names as keys.
    * @type {Object}
    */
   UserPod.userImageSalt_ = {};
 
   UserPod.prototype = {
     __proto__: HTMLDivElement.prototype,
 
+    // Column at which user pod is located.
+    column_: -1,
+
+    // Row at which user pod is located.
+    row_: -1,
+
     /** @override */
     decorate: function() {
       this.tabIndex = UserPodTabOrder.POD_INPUT;
       this.actionBoxAreaElement.tabIndex = UserPodTabOrder.ACTION_BOX;
 
       this.addEventListener('keydown', this.handlePodKeyDown_.bind(this));
       this.addEventListener('click', this.handleClickOnPod_.bind(this));
 
       this.signinButtonElement.addEventListener('click',
           this.activate.bind(this));
@@ skipping 90 matching lines @@
     },
 
     /**
      * Height number of pixels.
      */
     get height() {
       return this.offsetHeight;
     },
 
     /**
+     * User pod column.
+     * @type {?number}
+     */
+    set column(column) {
+      this.column_ = column;
+    },
+    get columns() {
+      return this.column_;
+    },
+
+    /**
+     * User pod row.
+     * @type {?number}
+     */
+    set row(row) {
+      this.row_ = row;
+    },
+    get row() {
+      return this.row_;
+    },
+
+    /**
      * Gets signed in indicator element.
      * @type {!HTMLDivElement}
      */
     get signedInIndicatorElement() {
       return this.querySelector('.signed-in-indicator');
     },
 
     /**
      * Gets image element.
      * @type {!HTMLImageElement}
@@ skipping 1088 matching lines @@
 
       var isDesktopUserManager = Oobe.getInstance().displayType ==
           DISPLAY_TYPE.DESKTOP_USER_MANAGER;
       this.userPodHeight_ = isDesktopUserManager ? DESKTOP_POD_HEIGHT :
                                                    CROS_POD_HEIGHT;
       // Same for Chrome OS and desktop.
       this.userPodWidth_ = POD_WIDTH;
     },
 
     /**
+     * Returns focused user pod.
+     * @type {Object}
+     */
+    get focusedPod() {

[dzhioev (left Google), 2014/05/21 17:30:32]

Why did you add this getter? As I can see, you only use it in
scrollFocusedPodIntoView where |focusedPod_| property can be used.

[Nikita (slow), 2014/05/22 15:11:50]

Right, not needed in latest impl, removed.

+      return this.focusedPod_;
+    },
+
+    /**
      * Returns all the pods in this pod row.
      * @type {NodeList}
      */
     get pods() {
       return Array.prototype.slice.call(this.children);
     },
 
     /**
      * Return true if user pod row has only single user pod in it.
      * @type {boolean}
@@ skipping 162 matching lines @@
      * @param {boolean} animated Whether to use init animation.
      */
     loadPods: function(users, animated) {
       this.users_ = users;
       this.userAddIsAnimated_ = animated;
 
       this.rebuildPods();
     },
 
     /**
+     * Scrolls focused user pod into view.
+     */
+    scrollFocusedPodIntoView: function() {
+      if (!this.focusedPod ||
+          this.focusedPod.column < 0 || this.focusedPod.row < 0) {
+        return;
+      }
+
+      $('scroll-container').scrollTop = $('scroll-container').offsetHeight *
+          USER_POD_ROW_SCROLL_STOPS[this.rows - 1][this.focusedPod.row];
+    },
+
+    /**
      * Rebuilds pod row using users_ and apps_ that were previously set or
      * updated.
      */
     rebuildPods: function() {
       var emptyPodRow = this.pods.length == 0;
 
       // Clear existing pods.
       this.innerHTML = '';
       this.focusedPod_ = undefined;
       this.activatedPod_ = undefined;
@@ skipping 150 matching lines @@
                                         BUBBLE_PADDING);
     },
 
     /**
      * Called when window was resized.
      */
     onWindowResize: function() {
       var layout = this.calculateLayout_();
       if (layout.columns != this.columns || layout.rows != this.rows)
         this.placePods_();
+
+      if (Oobe.getInstance().virtualKeyboardShown)
+        this.scrollFocusedPodIntoView();

[dzhioev (left Google), 2014/05/21 17:30:32]

Did you try to make the same in |focusPod|, where we change focused pod? It can
help with "if keyboard is already shown (i.e. no resize is happening) and user 
selects another user pod in different row no scrolling happens" problem.

[Nikita (slow), 2014/05/22 15:11:50]

Since virtual keyboard shows up after some delay first pod is focused and then
resize happens.

As for user pod scrolling when keyboard is already visible there's a bug which
resets focus for some reason, investigating.

     },
 
     /**
      * Returns width of podrow having |columns| number of columns.
      * @private
      */
     columnsToWidth_: function(columns) {
       var margin = MARGIN_BY_COLUMNS[columns];
       return 2 * POD_ROW_PADDING + columns *
           this.userPodWidth_ + (columns - 1) * margin;
@@ skipping 58 matching lines @@
         }
         if (pod.offsetWidth != width) {
           console.error('Pod offsetWidth (' + pod.offsetWidth +
               ') and POD_WIDTH (' + width + ') are not equal.');
         }
         if (index >= maxPodsNumber) {
            pod.hidden = true;
            return;
         }
         pod.hidden = false;
-        var column = index % columns;
-        var row = Math.floor(index / columns);
+        var column = pod.column = index % columns;
+        var row = pod.row = Math.floor(index / columns);
         pod.left = POD_ROW_PADDING + column * (width + margin);
         pod.top = POD_ROW_PADDING + row * height;
       });
       Oobe.getInstance().updateScreenSize(this.parentNode);
     },
 
     /**
      * Number of columns.
      * @type {?number}
      */
     set columns(columns) {
       // Cannot use 'columns' here.
       this.setAttribute('ncolumns', columns);
     },
     get columns() {
-      return this.getAttribute('ncolumns');
+      return parseInt(this.getAttribute('ncolumns'));
     },
 
     /**
      * Number of rows.
      * @type {?number}
      */
     set rows(rows) {
       // Cannot use 'rows' here.
       this.setAttribute('nrows', rows);
     },
     get rows() {
-      return this.getAttribute('nrows');
+      return parseInt(this.getAttribute('nrows'));
     },
 
     /**
      * Whether the pod is currently focused.
      * @param {UserPod} pod Pod to check for focus.
      * @return {boolean} Pod focus status.
      */
     isFocused: function(pod) {
       return this.focusedPod_ == pod;
     },
@@ skipping 383 matching lines @@
       if (this.podsWithPendingImages_.length == 0) {
         this.classList.remove('images-loading');
       }
     }
   };
 
   return {
     PodRow: PodRow
   };
 });