[es7] implement exponentiation operator proposal

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index d4fb62f02c041fce4d752fda56a4d979b564d622..f8a679aa30e9ad5cc7151959992286574f18bc03 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -644,6 +644,10 @@ class ParserTraits {
   // Rewrite all DestructuringAssignments in the current FunctionState.
   V8_INLINE void RewriteDestructuringAssignments();
 
+  V8_INLINE Expression* RewriteExponentiation(Expression* left,
+                                              Expression* right,
+                                              Token::Value op, int pos);
+
   V8_INLINE void QueueDestructuringAssignmentForRewriting(
       Expression* assignment);
   V8_INLINE void QueueNonPatternForRewriting(Expression* expr);
@@ -1035,6 +1039,10 @@ class Parser : public ParserBase<ParserTraits> {
 
   V8_INLINE void RewriteDestructuringAssignments();
 
+  V8_INLINE Expression* RewriteExponentiation(Expression* left,
+                                              Expression* right,
+                                              Token::Value op, int pos);
+
   friend class NonPatternRewriter;
   V8_INLINE Expression* RewriteSpreads(ArrayLiteral* lit);