Fix missing write barrier in store field stub.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 5c5c8423b4e4d53719a13742e22413f8e4b4bbd1..625751561ac49cecb349a7a98724fa224bf5ca0a 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -3455,6 +3455,18 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   if (!instr->transition().is_null()) {
     __ li(scratch, Operand(instr->transition()));
     __ sw(scratch, FieldMemOperand(object, HeapObject::kMapOffset));
+    if (instr->hydrogen()->NeedsWriteBarrierForMap()) {
+      Register temp = ToRegister(instr->TempAt(0));
+      // Update the write barrier for the map field.
+      __ RecordWriteField(object,
+                          HeapObject::kMapOffset,
+                          scratch,
+                          temp,
+                          kRAHasBeenSaved,
+                          kSaveFPRegs,
+                          OMIT_REMEMBERED_SET,
+                          OMIT_SMI_CHECK);
+    }
   }
 
   // Do the store.