Fix data races caused by compiler stats counters in the parser.

runtime/vm/parser.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_PARSER_H_
 #define VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "lib/invocation_mirror.h"
@@ skipping 252 matching lines @@
   RawDouble* CurrentDoubleLiteral() const;
   RawInteger* CurrentIntegerLiteral() const;
 
   // Sets parser to given token position in the stream.
   void SetPosition(intptr_t position);
 
   void ConsumeToken() {
     // Reset cache and advance the token.
     token_kind_ = Token::kILLEGAL;
     tokens_iterator_.Advance();
-    CompilerStats::num_tokens_consumed++;
+    if (FLAG_compiler_stats) CompilerStats::num_tokens_consumed++;
   }
   void ConsumeRightAngleBracket();
   void ExpectToken(Token::Kind token_expected);
   void ExpectSemicolon();
   void UnexpectedToken();
   String* ExpectUserDefinedTypeIdentifier(const char* msg);
   String* ExpectIdentifier(const char* msg);
   bool IsLiteral(const char* literal);
 
   void SkipIf(Token::Kind);
@@ skipping 434 matching lines @@
   intptr_t last_used_try_index_;
 
   bool unregister_pending_function_;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // VM_PARSER_H_