DevTools: Use JS symbols instead of strings for eligible events.

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 422b2b1159f2f0de0660882ffc5f6cfae604051f..00faa50fe523dd4191da8576dfea490f5f9d2ba0 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
@@ -149,11 +149,12 @@ WebInspector.DataGrid.CornerWidth = 14;
  */
 WebInspector.DataGrid.ColumnDescriptor;
 
+/** @enum {symbol} */
 WebInspector.DataGrid.Events = {
-    SelectedNode: "SelectedNode",
-    DeselectedNode: "DeselectedNode",
-    SortingChanged: "SortingChanged",
-    ColumnsResized: "ColumnsResized"
+    SelectedNode: Symbol("SelectedNode"),
+    DeselectedNode: Symbol("DeselectedNode"),
+    SortingChanged: Symbol("SortingChanged"),
+    ColumnsResized: Symbol("ColumnsResized")
 }
 
 /** @enum {string} */