Introduce LiteralsArray to hide it's implementation.

src/full-codegen/mips64/full-codegen-mips64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_MIPS64
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 1477 matching lines @@
   Label materialized;
   // Registers will be used as follows:
   // a5 = materialized value (RegExp literal)
   // a4 = JS function, literals array
   // a3 = literal index
   // a2 = RegExp pattern
   // a1 = RegExp flags
   // a0 = RegExp literal clone
   __ ld(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ld(a4, FieldMemOperand(a0, JSFunction::kLiteralsOffset));
-  int literal_offset =
-      FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
+  int literal_offset = LiteralsArray::OffsetOfLiteralAt(expr->literal_index());
   __ ld(a5, FieldMemOperand(a4, literal_offset));
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
   __ Branch(&materialized, ne, a5, Operand(at));
 
   // Create regexp literal using runtime function.
   // Result will be in v0.
   __ li(a3, Operand(Smi::FromInt(expr->literal_index())));
   __ li(a2, Operand(expr->pattern()));
   __ li(a1, Operand(expr->flags()));
   __ Push(a4, a3, a2, a1);
@@ skipping 3736 matching lines @@
          reinterpret_cast<uint64_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64