Add Smi::Zero and replace all Smi::FromInt(0) calls

src/heap/heap-inl.h

Index: src/heap/heap-inl.h
diff --git a/src/heap/heap-inl.h b/src/heap/heap-inl.h
index a8b98ac36c9ff6d1876b6b7f32e9d5d4fac26fb1..fc487d0cb70444f0de247121382644841a132828 100644
--- a/src/heap/heap-inl.h
+++ b/src/heap/heap-inl.h
@@ -742,9 +742,7 @@ void Heap::ExternalStringTable::ShrinkNewStrings(int position) {
 #endif
 }
 
-void Heap::ClearInstanceofCache() {
-  set_instanceof_cache_function(Smi::FromInt(0));
-}
+void Heap::ClearInstanceofCache() { set_instanceof_cache_function(Smi::kZero); }
 
 Oddball* Heap::ToBoolean(bool condition) {
   return condition ? true_value() : false_value();
@@ -752,8 +750,8 @@ Oddball* Heap::ToBoolean(bool condition) {
 
 
 void Heap::CompletelyClearInstanceofCache() {
-  set_instanceof_cache_map(Smi::FromInt(0));
-  set_instanceof_cache_function(Smi::FromInt(0));
+  set_instanceof_cache_map(Smi::kZero);
+  set_instanceof_cache_function(Smi::kZero);
 }
 
 
@@ -776,27 +774,27 @@ int Heap::NextScriptId() {
 }
 
 void Heap::SetArgumentsAdaptorDeoptPCOffset(int pc_offset) {
-  DCHECK(arguments_adaptor_deopt_pc_offset() == Smi::FromInt(0));
+  DCHECK(arguments_adaptor_deopt_pc_offset() == Smi::kZero);
   set_arguments_adaptor_deopt_pc_offset(Smi::FromInt(pc_offset));
 }
 
 void Heap::SetConstructStubDeoptPCOffset(int pc_offset) {
-  DCHECK(construct_stub_deopt_pc_offset() == Smi::FromInt(0));
+  DCHECK(construct_stub_deopt_pc_offset() == Smi::kZero);
   set_construct_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
 }
 
 void Heap::SetGetterStubDeoptPCOffset(int pc_offset) {
-  DCHECK(getter_stub_deopt_pc_offset() == Smi::FromInt(0));
+  DCHECK(getter_stub_deopt_pc_offset() == Smi::kZero);
   set_getter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
 }
 
 void Heap::SetSetterStubDeoptPCOffset(int pc_offset) {
-  DCHECK(setter_stub_deopt_pc_offset() == Smi::FromInt(0));
+  DCHECK(setter_stub_deopt_pc_offset() == Smi::kZero);
   set_setter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
 }
 
 void Heap::SetInterpreterEntryReturnPCOffset(int pc_offset) {
-  DCHECK(interpreter_entry_return_pc_offset() == Smi::FromInt(0));
+  DCHECK(interpreter_entry_return_pc_offset() == Smi::kZero);
   set_interpreter_entry_return_pc_offset(Smi::FromInt(pc_offset));
 }