Speed up identifying keywords in scanner, by using extra table.

runtime/vm/token.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_TOKEN_H_
 #define VM_TOKEN_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 190 matching lines @@
 #undef T
 
   enum Attribute {
     kNoAttribute     = 0,
     kKeyword         = 1 << 0,
     kPseudoKeyword   = 1 << 1,
   };
 
   static const Kind kFirstKeyword = kABSTRACT;
   static const Kind kLastKeyword = kWITH;
-  static const int  numKeywords = kLastKeyword - kFirstKeyword + 1;
+  static const int kNumKeywords = kLastKeyword - kFirstKeyword + 1;
 
   static bool IsAssignmentOperator(Kind tok) {
     return kASSIGN <= tok && tok <= kASSIGN_MOD;
   }
 
   static bool IsRelationalOperator(Kind tok) {
     return kLT <= tok && tok <= kGTE;
   }
 
   static bool IsEqualityOperator(Kind tok) {
@@ skipping 94 matching lines @@
   static const char* name_[];
   static const char* tok_str_[];
   static const uint8_t precedence_[];
   static const Attribute attributes_[];
 };
 
 
 }  // namespace dart
 
 #endif  // VM_TOKEN_H_