Use UniqueSet<T> and Unique<T> in HCheckMaps and HCheckValue.

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 059aa13322adb4dde769c9be9cf594fac8133cb4..30f7bf81520cf15dbccbadf75b59aedb796b2e79 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -5157,7 +5157,7 @@ void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
 
 void LCodeGen::DoCheckValue(LCheckValue* instr) {
   Register reg = ToRegister(instr->value());
-  Handle<HeapObject> object = instr->hydrogen()->object();
+  Handle<HeapObject> object = instr->hydrogen()->object().handle();
   AllowDeferredHandleDereference smi_check;
   if (isolate()->heap()->InNewSpace(*object)) {
     Register reg = ToRegister(instr->value());
@@ -5209,7 +5209,6 @@ void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
-  SmallMapList* map_set = instr->hydrogen()->map_set();
   __ ldr(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));
 
   DeferredCheckMaps* deferred = NULL;
@@ -5218,14 +5217,15 @@ void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
     __ bind(deferred->check_maps());
   }
 
+  UniqueSet<Map> map_set = instr->hydrogen()->map_set();
   Label success;
-  for (int i = 0; i < map_set->length() - 1; i++) {
-    Handle<Map> map = map_set->at(i);
+  for (int i = 0; i < map_set.size() - 1; i++) {
+    Handle<Map> map = map_set.at(i).handle();
     __ CompareMap(map_reg, map, &success);
     __ b(eq, &success);
   }
 
-  Handle<Map> map = map_set->last();
+  Handle<Map> map = map_set.at(map_set.size() - 1).handle();
   __ CompareMap(map_reg, map, &success);
   if (instr->hydrogen()->has_migration_target()) {
     __ b(ne, deferred->entry());