Amend DataView, ArrayBuffer, and TypedArray methods to use ToIndex.

src/js/runtime.js

Index: src/js/runtime.js
diff --git a/src/js/runtime.js b/src/js/runtime.js
index 216685fe4f2692eba560e0be9aedd03a919b6c01..4983d81df738f3a9754dd55efad580b2ae454d42 100644
--- a/src/js/runtime.js
+++ b/src/js/runtime.js
@@ -45,6 +45,13 @@ function ToPositiveInteger(x, rangeErrorIndex) {
 }
 
 
+function ToIndex(x, rangeErrorIndex) {
+  var i = TO_INTEGER(x) + 0;
+  if (i < 0 || i > kMaxSafeInteger) throw MakeRangeError(rangeErrorIndex);

[Dan Ehrenberg, 2016/06/29 19:13:43]

Pass x as an argument here?

[bakkot, 2016/06/29 19:25:09]

The messages passed to this function don't take an argument.

+  return i;
+}
+
+
 function MaxSimple(a, b) {
   return a > b ? a : b;
 }
@@ -94,6 +101,7 @@ utils.Export(function(to) {
   to.MaxSimple = MaxSimple;
   to.MinSimple = MinSimple;
   to.ToPositiveInteger = ToPositiveInteger;
+  to.ToIndex = ToIndex;
   to.SpeciesConstructor = SpeciesConstructor;
 });