Hook up more import/exports in natives.

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index b92a144c0cded375e072375f55e2ebea3902103e..70a88fb873cb18956514122aba63a1e115af01f0 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -8,10 +8,19 @@
 
 %CheckIsBootstrapping();
 
+// -------------------------------------------------------------------
+// Imports
+
 var GlobalMap = global.Map;
 var GlobalObject = global.Object;
 var GlobalSet = global.Set;
 
+var NumberIsNaN;
+
+utils.Import(function(from) {
+  NumberIsNaN = from.NumberIsNaN;
+});
+
 // -------------------------------------------------------------------
 
 function HashToEntry(table, hash, numBuckets) {
@@ -22,7 +31,7 @@ function HashToEntry(table, hash, numBuckets) {
 
 
 function SetFindEntry(table, numBuckets, key, hash) {
-  var keyIsNaN = $numberIsNaN(key);
+  var keyIsNaN = NumberIsNaN(key);
   for (var entry = HashToEntry(table, hash, numBuckets);
        entry !== NOT_FOUND;
        entry = ORDERED_HASH_SET_CHAIN_AT(table, entry, numBuckets)) {
@@ -30,7 +39,7 @@ function SetFindEntry(table, numBuckets, key, hash) {
     if (key === candidate) {
       return entry;
     }
-    if (keyIsNaN && $numberIsNaN(candidate)) {
+    if (keyIsNaN && NumberIsNaN(candidate)) {
       return entry;
     }
   }
@@ -40,7 +49,7 @@ function SetFindEntry(table, numBuckets, key, hash) {
 
 
 function MapFindEntry(table, numBuckets, key, hash) {
-  var keyIsNaN = $numberIsNaN(key);
+  var keyIsNaN = NumberIsNaN(key);
   for (var entry = HashToEntry(table, hash, numBuckets);
        entry !== NOT_FOUND;
        entry = ORDERED_HASH_MAP_CHAIN_AT(table, entry, numBuckets)) {
@@ -48,7 +57,7 @@ function MapFindEntry(table, numBuckets, key, hash) {
     if (key === candidate) {
       return entry;
     }
-    if (keyIsNaN && $numberIsNaN(candidate)) {
+    if (keyIsNaN && NumberIsNaN(candidate)) {
       return entry;
     }
   }
@@ -239,8 +248,8 @@ function SetForEach(f, receiver) {
 %FunctionSetLength(SetForEach, 1);
 
 // Set up the non-enumerable functions on the Set prototype object.
-$installGetter(GlobalSet.prototype, "size", SetGetSize);
-$installFunctions(GlobalSet.prototype, DONT_ENUM, [
+utils.InstallGetter(GlobalSet.prototype, "size", SetGetSize);
+utils.InstallFunctions(GlobalSet.prototype, DONT_ENUM, [
   "add", SetAdd,
   "has", SetHas,
   "delete", SetDelete,
@@ -427,8 +436,8 @@ function MapForEach(f, receiver) {
 %FunctionSetLength(MapForEach, 1);
 
 // Set up the non-enumerable functions on the Map prototype object.
-$installGetter(GlobalMap.prototype, "size", MapGetSize);
-$installFunctions(GlobalMap.prototype, DONT_ENUM, [
+utils.InstallGetter(GlobalMap.prototype, "size", MapGetSize);
+utils.InstallFunctions(GlobalMap.prototype, DONT_ENUM, [
   "get", MapGet,
   "set", MapSet,
   "has", MapHas,