Hydrogen: fix keyed loads with string keys

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index d7119239c78355de4ac1c97fcbe255847c36d4fe..ce1247fc0fac3386e6e9f1fd9435166addeb9250 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -1786,8 +1786,7 @@ class Property FINAL : public Expression {
     return STANDARD_STORE;
   }
   virtual IcCheckType GetKeyType() const OVERRIDE {
-    // PROPERTY key types currently aren't implemented for KeyedLoadICs.
-    return ELEMENT;
+    return KeyTypeField::decode(bit_field_);
   }
   bool IsUninitialized() const {
     return !is_for_call() && HasNoTypeInformation();
@@ -1801,6 +1800,9 @@ class Property FINAL : public Expression {
   void set_is_string_access(bool b) {
     bit_field_ = IsStringAccessField::update(bit_field_, b);
   }
+  void set_key_type(IcCheckType key_type) {
+    bit_field_ = KeyTypeField::update(bit_field_, key_type);
+  }
   void mark_for_call() {
     bit_field_ = IsForCallField::update(bit_field_, true);
   }
@@ -1838,6 +1840,7 @@ class Property FINAL : public Expression {
   class IsForCallField : public BitField8<bool, 0, 1> {};
   class IsUninitializedField : public BitField8<bool, 1, 1> {};
   class IsStringAccessField : public BitField8<bool, 2, 1> {};
+  class KeyTypeField : public BitField8<IcCheckType, 3, 1> {};
   uint8_t bit_field_;
   FeedbackVectorICSlot property_feedback_slot_;
   Expression* obj_;