[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 dbd8f1110108fdb17edd89958105f848e040e167..444a72338d8a7f2ae376256682d208cc3ef89679 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -636,6 +636,11 @@ class ParserTraits {
   // Rewrite all DestructuringAssignments in the current FunctionState.
   V8_INLINE void RewriteDestructuringAssignments();
 
+  V8_INLINE Expression* RewriteExponentiation(Expression* left,
+                                              Expression* right, int pos);
+  V8_INLINE Expression* RewriteAssignExponentiation(Expression* left,
+                                                    Expression* right, int pos);
+
   V8_INLINE void QueueDestructuringAssignmentForRewriting(
       Expression* assignment);
   V8_INLINE void QueueNonPatternForRewriting(Expression* expr);
@@ -1043,6 +1048,11 @@ class Parser : public ParserBase<ParserTraits> {
 
   V8_INLINE void RewriteDestructuringAssignments();
 
+  V8_INLINE Expression* RewriteExponentiation(Expression* left,
+                                              Expression* right, int pos);
+  V8_INLINE Expression* RewriteAssignExponentiation(Expression* left,
+                                                    Expression* right, int pos);
+
   friend class NonPatternRewriter;
   V8_INLINE Expression* RewriteSpreads(ArrayLiteral* lit);