Allocate and finalize a code object on x64 if the new compiler succeeds.

runtime/vm/flow_graph_compiler_x64.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_FLOW_GRAPH_COMPILER_X64_H_
 #define VM_FLOW_GRAPH_COMPILER_X64_H_
 
 #ifndef VM_FLOW_GRAPH_COMPILER_H_
 #error Include flow_graph_compiler.h instead of flow_graph_compiler_x64.h.
 #endif
@@ skipping 13 matching lines @@
                     const GrowableArray<BlockEntryInstr*>* blocks)
       : assembler_(assembler),
         parsed_function_(parsed_function),
         blocks_(blocks),
         pc_descriptors_list_(new CodeGenerator::DescriptorList()) { }
 
   virtual ~FlowGraphCompiler() { }
 
   void CompileGraph();
 
+  // Infrastructure copied from class CodeGenerator or stubbed out.
+  void FinalizePcDescriptors(const Code& code);
+  void FinalizeVarDescriptors(const Code& code);
+  void FinalizeExceptionHandlers(const Code& code);
+
  private:
   // Bail out of the flow graph compiler.  Does not return to the caller.
   void Bailout(const char* reason);
 
   // Each visit function compiles a type of instruction.
 #define DECLARE_VISIT(type)                             \
   virtual void Visit##type(type##Instr* instr);
   FOR_EACH_INSTRUCTION(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
@@ skipping 13 matching lines @@
   const GrowableArray<BlockEntryInstr*>* blocks_;
 
   CodeGenerator::DescriptorList* pc_descriptors_list_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_X64_H_