DevTools: Add lightweight StaticViewportControl

third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js

Index: third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js b/third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js
index 9fcec9a5ff7cae8b66fd405141e6e665700340ae..0bfe0f8ebc38d5a87e471926935fce1ab93cfee3 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui_lazy/FilteredListWidget.js
@@ -7,7 +7,7 @@
 /**
  * @constructor
  * @extends {WebInspector.VBox}
- * @implements {WebInspector.ViewportControl.Provider}
+ * @implements {WebInspector.StaticViewportControl.Provider}
  * @param {!WebInspector.FilteredListWidget.Delegate} delegate
  */
 WebInspector.FilteredListWidget = function(delegate)
@@ -33,7 +33,7 @@ WebInspector.FilteredListWidget = function(delegate)
     promptProxy.classList.add("filtered-list-widget-prompt-element");
 
     this._filteredItems = [];
-    this._viewportControl = new WebInspector.ViewportControl(this);
+    this._viewportControl = new WebInspector.StaticViewportControl(this);
     this._itemElementsContainer = this._viewportControl.element;
     this._itemElementsContainer.classList.add("container");
     this._itemElementsContainer.addEventListener("click", this._onClick.bind(this), false);
@@ -47,6 +47,9 @@ WebInspector.FilteredListWidget = function(delegate)
     this._updateShowMatchingItems();
     this._viewportControl.refresh();
     this._prompt.autoCompleteSoon(true);
+
+    /** @typedef {!Array.<!Element>} */
+    this._elements = [];
 }
 
 /**
@@ -249,6 +252,7 @@ WebInspector.FilteredListWidget.prototype = {
                     break;
                 }
             }
+            this._elements = [];
             this._viewportControl.invalidate();
             if (!query)
                 this._selectedIndexInFiltered = 0;
@@ -343,7 +347,7 @@ WebInspector.FilteredListWidget.prototype = {
             this._selectedElement.classList.remove("selected");
         this._viewportControl.scrollItemIntoView(index, makeLast);
         this._selectedIndexInFiltered = index;
-        this._selectedElement = this._viewportControl.renderedElementAt(index);
+        this._selectedElement = this._elements[index];
         if (this._selectedElement)
             this._selectedElement.classList.add("selected");
     },
@@ -379,7 +383,7 @@ WebInspector.FilteredListWidget.prototype = {
         if (!this._rowHeight) {
             var delegateIndex = this._filteredItems[index];
             var element = this._createItemElement(delegateIndex);
-            this._rowHeight = WebInspector.measurePreferredSize(element, this._viewportControl.contentElement()).height;
+            this._rowHeight = WebInspector.measurePreferredSize(element, this._itemElementsContainer).height;
         }
         return this._rowHeight;
     },
@@ -387,22 +391,13 @@ WebInspector.FilteredListWidget.prototype = {
     /**
      * @override
      * @param {number} index
-     * @return {!WebInspector.ViewportElement}
+     * @return {!Element}
      */
     itemElement: function(index)
     {
-        var delegateIndex = this._filteredItems[index];
-        var element = this._createItemElement(delegateIndex);
-        return new WebInspector.StaticViewportElement(element);
-    },
-
-    /**
-     * @override
-     * @return {number}
-     */
-    minimumRowHeight: function()
-    {
-        return this.fastHeight(0);
+        if (!this._elements[index])
+            this._elements[index] = this._createItemElement(this._filteredItems[index]);
+        return this._elements[index];
     },
 
     __proto__: WebInspector.VBox.prototype