Refactor scroll updates during flexbox layout.

third_party/WebKit/Source/web/resources/listPicker.js

 "use strict";
 // Copyright (c) 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.
 
 var global = {
     argumentsReceived: false,
     params: null,
     picker: null
 };
@@ skipping 203 matching lines @@
         }, 0);
         event.preventDefault();
     }
 };
 
 ListPicker.prototype._fixWindowSize = function() {
     this._selectElement.style.height = "";
     var zoom = this._config.zoomFactor;
     var maxHeight = this._selectElement.offsetHeight * zoom;
     var noScrollHeight = (this._calculateScrollHeight() + ListPicker.ListboxSelectBorder * 2) * zoom;
-    var scrollbarWidth = getScrollbarWidth() * zoom;
     var elementOffsetWidth = this._selectElement.offsetWidth * zoom;
     var desiredWindowHeight = noScrollHeight;
     var desiredWindowWidth = elementOffsetWidth;
     var expectingScrollbar = false;
     if (desiredWindowHeight > maxHeight) {
         desiredWindowHeight = maxHeight;
         // Setting overflow to auto does not increase width for the scrollbar
         // so we need to do it manually.
-        desiredWindowWidth += scrollbarWidth;
         expectingScrollbar = true;
     }
     desiredWindowWidth = Math.max(this._config.anchorRectInScreen.width, desiredWindowWidth);
     var windowRect = adjustWindowRect(desiredWindowWidth, desiredWindowHeight, elementOffsetWidth, 0);
     // If the available screen space is smaller than maxHeight, we will get an unexpected scrollbar.
     if (!expectingScrollbar && windowRect.height < noScrollHeight) {
-        desiredWindowWidth = windowRect.width + scrollbarWidth;
+        desiredWindowWidth = windowRect.width;
         windowRect = adjustWindowRect(desiredWindowWidth, windowRect.height, windowRect.width, windowRect.height);
     }
     this._selectElement.style.width = (windowRect.width / zoom) + "px";
     this._selectElement.style.height = (windowRect.height / zoom) + "px";
     this._element.style.height = (windowRect.height / zoom) + "px";
     setWindowRect(windowRect);
 };
 
 ListPicker.prototype._calculateScrollHeight = function() {
     // Element.scrollHeight returns an integer value but this calculate the
@@ skipping 195 matching lines @@
     }
     this._applyItemStyle(element, config.style);
 };
 
 if (window.dialogArguments) {
     initialize(dialogArguments);
 } else {
     window.addEventListener("message", handleMessage, false);
     window.setTimeout(handleArgumentsTimeout, 1000);
 }