[stubs] Further optimize Load/StoreGlobalViaContext stubs.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index f4bd4179790f34409068a04ce518c46c6ecca4c7..2689e42d5c1d89e38bb3f698b6503be70e5bc965 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -5564,12 +5564,11 @@ void HOptimizedGraphBuilder::VisitVariableProxy(VariableProxy* expr) {
       } else if (variable->IsGlobalSlot()) {
         DCHECK(variable->index() > 0);
         DCHECK(variable->IsStaticGlobalObjectProperty());
-        // Each var occupies two slots in the context: for reads and writes.
         int slot_index = variable->index();
         int depth = scope()->ContextChainLength(variable->scope());
 
         HLoadGlobalViaContext* instr =
-            New<HLoadGlobalViaContext>(variable->name(), depth, slot_index);
+            New<HLoadGlobalViaContext>(depth, slot_index);
         return ast_context()->ReturnInstruction(instr, expr->id());
 
       } else {
@@ -6796,12 +6795,11 @@ void HOptimizedGraphBuilder::HandleGlobalVariableAssignment(
   } else if (var->IsGlobalSlot()) {
     DCHECK(var->index() > 0);
     DCHECK(var->IsStaticGlobalObjectProperty());
-    // Each var occupies two slots in the context: for reads and writes.
-    int slot_index = var->index() + 1;
+    int slot_index = var->index();
     int depth = scope()->ContextChainLength(var->scope());
 
     HStoreGlobalViaContext* instr = Add<HStoreGlobalViaContext>(
-        var->name(), value, depth, slot_index, function_language_mode());
+        value, depth, slot_index, function_language_mode());
     USE(instr);
     DCHECK(instr->HasObservableSideEffects());
     Add<HSimulate>(ast_id, REMOVABLE_SIMULATE);