First part of inspecting local variables

runtime/vm/ast_printer.cc

Index: runtime/vm/ast_printer.cc
===================================================================
--- runtime/vm/ast_printer.cc	(revision 2646)
+++ runtime/vm/ast_printer.cc	(working copy)
@@ -417,7 +417,7 @@
     } else if (var->owner()->function_level() != 0) {
       OS::Print(" lev %d", var->owner()->function_level());
     }
-    OS::Print(")");
+    OS::Print(" valid %d-%d)", var->token_index(), scope->end_token_index());
   }
   const LocalScope* child = scope->child();
   while (child != NULL) {
@@ -465,7 +465,7 @@
         OS::Print(" ctx %d", param->owner()->context_level());
       }
     }
-    OS::Print(")");
+    OS::Print(" valid %d-%d)", param->token_index(), scope->end_token_index());
     pos++;
   }
   // Visit remaining non-parameter variables and children scopes.