Use NeedsContext() instead of comparing num_heap_slots().

src/crankshaft/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.7
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 153 matching lines @@
     SaveCallerDoubles();
   }
   return !is_aborted();
 }
 
 
 void LCodeGen::DoPrologue(LPrologue* instr) {
   Comment(";;; Prologue begin");
 
   // Possibly allocate a local context.
-  if (info()->scope()->num_heap_slots() > 0) {
+  if (info()->scope()->NeedsContext()) {
     Comment(";;; Allocate local context");
     bool need_write_barrier = true;
     // Argument to NewContext is the function, which is in a1.
     int slots = info()->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     Safepoint::DeoptMode deopt_mode = Safepoint::kNoLazyDeopt;
     if (info()->scope()->is_script_scope()) {
       __ push(a1);
       __ Push(info()->scope()->GetScopeInfo(info()->isolate()));
       __ CallRuntime(Runtime::kNewScriptContext);
       deopt_mode = Safepoint::kLazyDeopt;
@@ skipping 5349 matching lines @@
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8