Add a helper function for allocation of deoptimization history.

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 1311 matching lines @@
   // It is not the only Code object that points to this function.
   RawCode* CurrentCode() const { return raw_ptr()->code_; }
 
   RawCode* unoptimized_code() const { return raw_ptr()->unoptimized_code_; }
   void set_unoptimized_code(const Code& value) const;
   static intptr_t code_offset() { return OFFSET_OF(RawFunction, code_); }
   inline bool HasCode() const;
 
   RawArray* deopt_history() const { return raw_ptr()->deopt_history_; }
   void set_deopt_history(const Array& value) const;
+  // If not yet present, allocate deoptimization history array.
+  void EnsureDeoptHistory() const;
 
   // Returns true if there is at least one debugger breakpoint
   // set in this function.
   bool HasBreakpoint() const;
 
   RawContextScope* context_scope() const;
   void set_context_scope(const ContextScope& value) const;
 
   // Enclosing function of this local function.
   RawFunction* parent_function() const;
@@ skipping 4478 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_