Pass undefined to JS builtins when called with implicit receiver.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 100f4d2fdf9be1616265a71a90e3041870214009..9e1153a9fe479d606b1f7b536b69d87d866dc037 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -146,11 +146,11 @@ bool LCodeGen::GeneratePrologue() {
   // fp: Caller's frame pointer.
   // lr: Caller's pc.
 
-  // Strict mode functions need to replace the receiver with undefined
-  // when called as functions (without an explicit receiver
-  // object). r5 is zero for method calls and non-zero for function
-  // calls.
-  if (info_->is_strict_mode()) {
+  // Strict mode functions and builtins need to replace the receiver
+  // with undefined when called as functions (without an explicit
+  // receiver object). r5 is zero for method calls and non-zero for
+  // function calls.
+  if (info_->is_strict_mode() || info_->is_native()) {
     Label ok;
     __ cmp(r5, Operand(0));
     __ b(eq, &ok);