Cosmetic: Add macros for NaN, undefined and Infinity to native js code.

src/object-observe.js

Index: src/object-observe.js
diff --git a/src/object-observe.js b/src/object-observe.js
index b09c42db73b619eadff98e74fad6b2d572fb763a..9c7ac3889eb573b04ae6c4612dc5d4791174fda0 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -72,12 +72,12 @@ function ObservationWeakMap(map) {
 ObservationWeakMap.prototype = {
   get: function(key) {
     key = %UnwrapGlobalProxy(key);
-    if (!IS_SPEC_OBJECT(key)) return void 0;
+    if (!IS_SPEC_OBJECT(key)) return UNDEFINED;
     return %WeakCollectionGet(this.map_, key);
   },
   set: function(key, value) {
     key = %UnwrapGlobalProxy(key);
-    if (!IS_SPEC_OBJECT(key)) return void 0;
+    if (!IS_SPEC_OBJECT(key)) return UNDEFINED;
     %WeakCollectionSet(this.map_, key, value);
   },
   has: function(key) {
@@ -492,7 +492,7 @@ function ObjectNotifierPerformChange(changeType, changeFn) {
 
   ObjectInfoAddPerformingType(objectInfo, changeType);
   try {
-    %_CallFunction(void 0, changeFn);
+    %_CallFunction(UNDEFINED, changeFn);
   } finally {
     ObjectInfoRemovePerformingType(objectInfo, changeType);
   }
@@ -525,7 +525,7 @@ function CallbackDeliverPending(callback) {
   %MoveArrayContents(callbackInfo, delivered);
 
   try {
-    %_CallFunction(void 0, delivered, callback);
+    %_CallFunction(UNDEFINED, delivered, callback);
   } catch (ex) {}
   return true;
 }