Extend assembler with ability to produce comments for the generated code.

runtime/vm/flow_graph_compiler_arm.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/longjump.h"
@@ skipping 30 matching lines @@
 void FlowGraphCompiler::FinalizeVarDescriptors(const Code& code) {
   UNIMPLEMENTED();
 }
 
 
 void FlowGraphCompiler::FinalizeExceptionHandlers(const Code& code) {
   UNIMPLEMENTED();
 }
 
 
+void FlowGraphCompiler::FinalizeComments(const Code& code) {
+  UNIMPLEMENTED();
+}
+
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM