ES6: Implement object literal property shorthand

src/token.h

Index: src/token.h
diff --git a/src/token.h b/src/token.h
index 9c719b827e328b339b37ea9f7358171e6742d6d7..bab925accecb0e3245247beb83f84c58f57ef510 100644
--- a/src/token.h
+++ b/src/token.h
@@ -6,6 +6,7 @@
 #define V8_TOKEN_H_
 
 #include "src/base/logging.h"
+#include "src/globals.h"
 
 namespace v8 {
 namespace internal {
@@ -187,6 +188,24 @@ class Token {
     return token_type[tok] == 'K';
   }
 
+  static bool IsIdentifier(Value tok, StrictMode strict_mode,
+                           bool is_generator) {
+    switch (tok) {
+      case IDENTIFIER:
+        return true;
+      case FUTURE_STRICT_RESERVED_WORD:
+      case LET:
+      case STATIC:
+        return strict_mode == SLOPPY;
+      case YIELD:
+        return !is_generator && strict_mode == SLOPPY;
+      default:
+        return false;
+    }
+    UNREACHABLE();
+    return false;
+  }
+
   static bool IsAssignmentOp(Value tok) {
     return INIT_VAR <= tok && tok <= ASSIGN_MOD;
   }