DevTools: [Console] Separate height caching from willHide event

Source/devtools/front_end/ui/ViewportControl.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 70 matching lines @@
      * @return {?WebInspector.ViewportElement}
      */
     itemElement: function(index) { return null; }
 }
 
 /**
  * @interface
  */
 WebInspector.ViewportElement = function() { }
 WebInspector.ViewportElement.prototype = {
+    cacheFastHeight: function() { },
+
     willHide: function() { },
 
     wasShown: function() { },
 
     /**
      * @return {!Element}
      */
     element: function() { },
 }
 
 /**
  * @constructor
  * @implements {WebInspector.ViewportElement}
  * @param {!Element} element
  */
 WebInspector.StaticViewportElement = function(element)
 {
     this._element = element;
 }
 
 WebInspector.StaticViewportElement.prototype = {
+    cacheFastHeight: function() { },
+
     willHide: function() { },
 
     wasShown: function() { },
 
     /**
      * @return {!Element}
      */
     element: function()
     {
         return this._element;
@@ skipping 201 matching lines @@
     },
 
     refresh: function()
     {
         if (!this.element.clientHeight)
             return;  // Do nothing for invisible controls.
 
         var itemCount = this._provider.itemCount();
         if (!itemCount) {
             for (var i = 0; i < this._renderedItems.length; ++i)
+                this._renderedItems[i].cacheFastHeight();
+            for (var i = 0; i < this._renderedItems.length; ++i)
                 this._renderedItems[i].willHide();
             this._renderedItems = [];
             this._contentElement.removeChildren();
             this._topGapElement.style.height = "0px";
             this._bottomGapElement.style.height = "0px";
             this._firstVisibleIndex = -1;
             this._lastVisibleIndex = -1;
             return;
         }
 
         var selection = window.getSelection();
         var shouldRestoreSelection = this._updateSelectionModel(selection);
 
         var visibleFrom = this.element.scrollTop;
         var clientHeight = this.element.clientHeight;
         var shouldStickToBottom = this._stickToBottom && this.element.isScrolledToBottom();
 
         if (this._cumulativeHeights && itemCount !== this._cumulativeHeights.length)
             delete this._cumulativeHeights;
         for (var i = 0; i < this._renderedItems.length; ++i) {
-            this._renderedItems[i].willHide();
+            this._renderedItems[i].cacheFastHeight();
             // Tolerate 1-pixel error due to double-to-integer rounding errors.
             if (this._cumulativeHeights && Math.abs(this._cachedItemHeight(this._firstVisibleIndex + i) - this._provider.fastHeight(i + this._firstVisibleIndex)) > 1)
                 delete this._cumulativeHeights;
         }
         this._rebuildCumulativeHeightsIfNeeded();
         if (shouldStickToBottom) {
             this._lastVisibleIndex = itemCount - 1;
             this._firstVisibleIndex = Math.max(Array.prototype.lowerBound.call(this._cumulativeHeights, this._cumulativeHeights[this._cumulativeHeights.length - 1] - clientHeight), 0);
         } else {
             this._firstVisibleIndex = Math.max(Array.prototype.lowerBound.call(this._cumulativeHeights, visibleFrom), 0);
             this._lastVisibleIndex = Math.min(Array.prototype.upperBound.call(this._cumulativeHeights, visibleFrom + clientHeight), itemCount - 1);
         }
         var topGapHeight = this._cumulativeHeights[this._firstVisibleIndex - 1] || 0;
         var bottomGapHeight = this._cumulativeHeights[this._cumulativeHeights.length - 1] - this._cumulativeHeights[this._lastVisibleIndex];
 
         this._topGapElement.style.height = topGapHeight + "px";
         this._bottomGapElement.style.height = bottomGapHeight + "px";
         this._topGapElement._active = !!topGapHeight;
         this._bottomGapElement._active = !!bottomGapHeight;
 
         this._contentElement.style.setProperty("height", "10000000px");
+        for (var i = 0; i < this._renderedItems.length; ++i)
+            this._renderedItems[i].willHide();
         this._renderedItems = [];
         this._contentElement.removeChildren();
         for (var i = this._firstVisibleIndex; i <= this._lastVisibleIndex; ++i) {
             var viewportElement = this._provider.itemElement(i);
             this._contentElement.appendChild(viewportElement.element());
             this._renderedItems.push(viewportElement);
             viewportElement.wasShown();
         }
 
         this._contentElement.style.removeProperty("height");
@@ skipping 120 matching lines @@
 
     /**
      * @param {number} index
      */
     forceScrollItemToBeLast: function(index)
     {
         this._rebuildCumulativeHeightsIfNeeded();
         this.element.scrollTop = this._cumulativeHeights[index] - this.element.clientHeight;
     }
 }