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

chrome/browser/resources/login/user_pod_row.js

Index: chrome/browser/resources/login/user_pod_row.js
diff --git a/chrome/browser/resources/login/user_pod_row.js b/chrome/browser/resources/login/user_pod_row.js
index b6fbe379c1c7c0bde11dcca114e136ba8f6b1c2e..57bb80fb463d58514ca7086e27d6c2bc0b6b16f8 100644
--- a/chrome/browser/resources/login/user_pod_row.js
+++ b/chrome/browser/resources/login/user_pod_row.js
@@ -47,6 +47,15 @@ cr.define('login', function() {
   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
@@ -156,6 +165,12 @@ cr.define('login', function() {
   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;
@@ -266,6 +281,28 @@ cr.define('login', function() {
     },
 
     /**
+     * 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}
      */
@@ -1374,6 +1411,14 @@ cr.define('login', function() {
     },
 
     /**
+     * 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}
      */
@@ -1556,6 +1601,19 @@ cr.define('login', function() {
     },
 
     /**
+     * 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.
      */
@@ -1726,6 +1784,9 @@ cr.define('login', 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.

     },
 
     /**
@@ -1804,8 +1865,8 @@ cr.define('login', function() {
            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;
       });
@@ -1821,7 +1882,7 @@ cr.define('login', function() {
       this.setAttribute('ncolumns', columns);
     },
     get columns() {
-      return this.getAttribute('ncolumns');
+      return parseInt(this.getAttribute('ncolumns'));
     },
 
     /**
@@ -1833,7 +1894,7 @@ cr.define('login', function() {
       this.setAttribute('nrows', rows);
     },
     get rows() {
-      return this.getAttribute('nrows');
+      return parseInt(this.getAttribute('nrows'));
     },
 
     /**