[Atomics] code stubs for atomic operations

src/js/harmony-atomics.js

Index: src/js/harmony-atomics.js
diff --git a/src/js/harmony-atomics.js b/src/js/harmony-atomics.js
index 9f80227426b41f106d34bf1604702be0ad2ae377..598468084a3cff9f89c991d7df4370ef66a44cf5 100644
--- a/src/js/harmony-atomics.js
+++ b/src/js/harmony-atomics.js
@@ -62,12 +62,6 @@ function AtomicsCompareExchangeJS(sta, index, oldValue, newValue) {
   return %_AtomicsCompareExchange(sta, index, oldValue, newValue);
 }
 
-function AtomicsLoadJS(sta, index) {
-  CheckSharedIntegerTypedArray(sta);
-  index = ValidateIndex(index, %_TypedArrayGetLength(sta));
-  return %_AtomicsLoad(sta, index);
-}
-
 function AtomicsStoreJS(sta, index, value) {
   CheckSharedIntegerTypedArray(sta);
   index = ValidateIndex(index, %_TypedArrayGetLength(sta));
@@ -161,13 +155,9 @@ function AtomicsFutexWakeOrRequeueJS(ia, index1, count, value, index2) {
 
 // -------------------------------------------------------------------
 
-function AtomicsConstructor() {}
-
-var Atomics = new AtomicsConstructor();
+var Atomics = global.Atomics;
 
-%InternalSetPrototype(Atomics, GlobalObject.prototype);
-%AddNamedProperty(global, "Atomics", Atomics, DONT_ENUM);
-%FunctionSetInstanceClassName(AtomicsConstructor, 'Atomics');
+// The Atomics global is defined by the bootstrapper.
 
 %AddNamedProperty(Atomics, toStringTagSymbol, "Atomics", READ_ONLY | DONT_ENUM);
 
@@ -179,8 +169,9 @@ utils.InstallConstants(Atomics, [
 ]);
 
 utils.InstallFunctions(Atomics, DONT_ENUM, [
+  // TODO(binji): remove the rest of the (non futex) Atomics functions as they
+  // become builtins.
   "compareExchange", AtomicsCompareExchangeJS,
-  "load", AtomicsLoadJS,
   "store", AtomicsStoreJS,
   "add", AtomicsAddJS,
   "sub", AtomicsSubJS,