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

src/builtins/builtins-array.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins/builtins.h"
 #include "src/builtins/builtins-utils.h"
 
 #include "src/code-factory.h"
 #include "src/elements.h"
 
@@ skipping 1066 matching lines @@
     // holes across concat operations.
     storage =
         isolate->factory()->NewFixedArrayWithHoles(estimate_result_length);
   } else if (is_array_species) {
     // TODO(126): move 25% pre-allocation logic into Dictionary::Allocate
     uint32_t at_least_space_for =
         estimate_nof_elements + (estimate_nof_elements >> 2);
     storage = SeededNumberDictionary::New(isolate, at_least_space_for);
   } else {
     DCHECK(species->IsConstructor());
-    Handle<Object> length(Smi::FromInt(0), isolate);
+    Handle<Object> length(Smi::kZero, isolate);
     Handle<Object> storage_object;
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, storage_object,
         Execution::New(isolate, species, species, 1, &length));
     storage = storage_object;
   }
 
   ArrayConcatVisitor visitor(isolate, storage, fast_case);
 
   for (int i = 0; i < argument_count; i++) {
@@ skipping 960 matching lines @@
   assembler->Bind(&return_not_found);
   assembler->Return(assembler->NumberConstant(-1));
 
   assembler->Bind(&call_runtime);
   assembler->Return(assembler->CallRuntime(Runtime::kArrayIndexOf, context,
                                            array, search_element, start_from));
 }
 
 }  // namespace internal
 }  // namespace v8