[stubs] Unify (and optimize) implementation of ToObject.

src/full-codegen/x87/full-codegen-x87.cc

Index: src/full-codegen/x87/full-codegen-x87.cc
diff --git a/src/full-codegen/x87/full-codegen-x87.cc b/src/full-codegen/x87/full-codegen-x87.cc
index 88ac788be49dc301f410d8cbc41e0efa4863e701..59e5dc559b456d2222e18cd1e91098fab2413bbb 100644
--- a/src/full-codegen/x87/full-codegen-x87.cc
+++ b/src/full-codegen/x87/full-codegen-x87.cc
@@ -1018,8 +1018,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
   __ j(above_equal, &done_convert, Label::kNear);
   __ bind(&convert);
-  __ push(eax);
-  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
   __ bind(&done_convert);
   PrepareForBailoutForId(stmt->ToObjectId(), TOS_REG);
   __ push(eax);
@@ -3912,6 +3912,19 @@ void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitToObject(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  DCHECK_EQ(1, args->length());
+
+  // Load the argument into eax and convert it.
+  VisitForAccumulatorValue(args->at(0));
+
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
+  context()->Plug(eax);
+}
+
+
 void FullCodeGenerator::EmitStringCharFromCode(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);