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

src/full-codegen/arm/full-codegen-arm.cc

Index: src/full-codegen/arm/full-codegen-arm.cc
diff --git a/src/full-codegen/arm/full-codegen-arm.cc b/src/full-codegen/arm/full-codegen-arm.cc
index 43d9aed55bc5d93182db7252e1bf4d914dfe1d3f..5320c45db138ee157064676984ae6627da529c81 100644
--- a/src/full-codegen/arm/full-codegen-arm.cc
+++ b/src/full-codegen/arm/full-codegen-arm.cc
@@ -1083,8 +1083,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ CompareObjectType(r0, r1, r1, FIRST_SPEC_OBJECT_TYPE);
   __ b(ge, &done_convert);
   __ bind(&convert);
-  __ push(r0);
-  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
   __ bind(&done_convert);
   PrepareForBailoutForId(stmt->ToObjectId(), TOS_REG);
   __ push(r0);
@@ -4018,6 +4018,19 @@ void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitToObject(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  DCHECK_EQ(1, args->length());
+
+  // Load the argument into r0 and convert it.
+  VisitForAccumulatorValue(args->at(0));
+
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
+  context()->Plug(r0);
+}
+
+
 void FullCodeGenerator::EmitStringCharFromCode(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);