Lazily generate local var descriptors.

runtime/vm/parser_test.cc

 // Copyright (c) 2011, 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/ast_printer.h"
 #include "vm/class_finalizer.h"
 #include "vm/debugger.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
@@ skipping 195 matching lines @@
                      const Dart_CodeLocation& loc) {
   DebuggerStackTrace* stack =
       Isolate::Current()->debugger()->StackTrace();
   intptr_t num_frames = stack->Length();
   const int kBufferLen = 2048;
   char* buffer = new char[kBufferLen];
   char* pos = buffer;
   LocalVarDescriptors& var_desc = LocalVarDescriptors::Handle();
   for (intptr_t i = 0; i < num_frames; i++) {
     ActivationFrame* frame = stack->FrameAt(i);
-    var_desc = frame->code().var_descriptors();
+    var_desc = frame->code().GetLocalVarDescriptors();
     const char* var_str = SkipIndex(var_desc.ToCString());
     const char* function_str = String::Handle(
         frame->function().QualifiedUserVisibleName()).ToCString();
     pos += OS::SNPrint(pos, (kBufferLen - (pos - buffer)),
                        "%s\n%s",
                        function_str,
                        var_str);
     delete [] var_str;
   }
   pos[0] = '\0';
@@ skipping 332 matching lines @@
       "a\n"
       " 0 CurrentCtx    scope=0   begin=0   end=0"
       "   name=:current_context_var\n"
       " 1 ContextLevel  level=1   scope=2   begin=3   end=76\n"
       " 2 ContextVar    level=1   begin=9   end=76  name=x\n"
       " 3 StackVar      scope=2   begin=11  end=76  name=b\n",
       CaptureVarsAtLine(lib, "a", 10));
 }
 
 }  // namespace dart