[turbolizer] Performance improvements for selection in graph & schedule

tools/turbolizer/selection.js

 // Copyright 2015 the V8 project 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 Selection = function(handler) {
   this.handler = handler;
   this.selectionBase = null;
   this.lastSelection = null;
   this.selection = new Set();
 }
 
 
 Selection.prototype.isEmpty = function() {
   return this.selection.size == 0;
 }
 
 
 Selection.prototype.clear = function() {
   var handler = this.handler;
   this.selectionBase = null;
   this.lastSelection = null;
   handler.select(this.selection, false);
   handler.clear();
   this.selection = new Set();
 }
 
 
 count = 0;
 
-Selection.prototype.select = function(s, selected) {
+Selection.prototype.select = function(s, isSelected) {
   var handler = this.handler;
-  if (this.selection.has(s) && !selected) {
-    handler.select([s], false);
-    this.selection.delete(s);
-    return;
+  if (!(Symbol.iterator in Object(s))) { s = [s]; }
+  if (isSelected) {
+    let first = true;
+    for (let i of s) {
+      if (first) {
+        this.selectionBase = i;
+        this.lastSelection = i;
+        first = false;
+      }
+      this.selection.add(i);
+    }
+  } else {
+    let unselectSet = new Set();
+    for (let i of s) {
+      if (this.selection.has(i)) {
+        unselectSet.add(i);
+        this.selection.delete(i);
+      }
+    }
   }
-
-  if (selected) {
-    this.selection.add(s);
-    this.selectionBase = s;
-    this.lastSelection = s;
-    handler.select(this.selection, selected);
-  }
+  handler.select(this.selection, isSelected);
 }
 
 
 Selection.prototype.extendTo = function(pos) {
   if (pos == this.lastSelection || this.lastSelection === null) return;
 
   var handler = this.handler;
   var pos_diff = handler.selectionDifference(pos, true, this.lastSelection, false);
   var unselect_diff = [];
   if (pos_diff.length == 0) {
@@ skipping 35 matching lines @@
 
 
 Selection.prototype.detachSelection = function() {
   var result = new Set();
   for (var i of this.selection) {
     result.add(i);
   }
   this.clear();
   return result;
 }