[DevTools] Reduce relayouts in DataGrid and ViewportControl.

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

Index: third_party/WebKit/Source/devtools/front_end/ui_lazy/DataGrid.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui_lazy/DataGrid.js b/third_party/WebKit/Source/devtools/front_end/ui_lazy/DataGrid.js
index a095a14484483b5a3a6cfaf4065a98ffdbdc9d14..1538fab3ebe2e1c237c3165d1d50a2bb542a4970 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui_lazy/DataGrid.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui_lazy/DataGrid.js
@@ -86,6 +86,9 @@ WebInspector.DataGrid = function(columnsArray, editCallback, deleteCallback, ref
     this._bottomFillerRow = createElementWithClass("tr", "data-grid-filler-row revealed");
     this.setVerticalPadding(0, 0);
 
+    /** @type {boolean} */
+    this._inline = false;
+
     /** @type {!Array.<!WebInspector.DataGrid.ColumnDescriptor>} */
     this._columnsArray = columnsArray;
     /** @type {!Array.<!WebInspector.DataGrid.ColumnDescriptor>} */
@@ -314,6 +317,7 @@ WebInspector.DataGrid.prototype = {
     {
         this.element.classList.add("inline");
         this._cornerWidth = 0;
+        this._inline = true;
         this.updateWidths();
     },
 
@@ -694,6 +698,15 @@ WebInspector.DataGrid.prototype = {
         return this._scrollContainer;
     },
 
+    /**
+     * @override
+     * @return {!Array.<!Element>}
+     */
+    elementsToRestoreScrollPositionsFor: function()
+    {
+        return this._inline ? [] : [this._scrollContainer];
+    },
+
     _positionResizers: function()
     {
         var headerTableColumns = this._headerTableColumnGroup.children;