Add interceptor support for symbols

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 4ba4c95f42f43b6c095445bb76582acb16147bdc..2a8f00f07b669c41947e60ba9b81b08dc2fb5482 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2798,10 +2798,12 @@ class FixedArray: public FixedArrayBase {
                                      int new_length,
                                      PretenureFlag pretenure = NOT_TENURED);
 
+  enum KeyFilter { ALL_KEYS, NON_SYMBOL_KEYS };
+
   // Add the elements of a JSArray to this FixedArray.
   MUST_USE_RESULT static MaybeHandle<FixedArray> AddKeysFromArrayLike(
-      Handle<FixedArray> content,
-      Handle<JSObject> array);
+      Handle<FixedArray> content, Handle<JSObject> array,
+      KeyFilter filter = ALL_KEYS);
 
   // Computes the union of keys and return the result.
   // Used for implementing "for (n in object) { }"
@@ -10734,6 +10736,12 @@ class InterceptorInfo: public Struct {
   DECL_ACCESSORS(deleter, Object)
   DECL_ACCESSORS(enumerator, Object)
   DECL_ACCESSORS(data, Object)
+  DECL_BOOLEAN_ACCESSORS(can_intercept_symbols)
+
+  // TODO(wingo): Remove flags field once all interceptors can intercept
+  // symbols.
+  inline int flags() const;
+  inline void set_flags(int flags);
 
   DECLARE_CAST(InterceptorInfo)
 
@@ -10747,7 +10755,10 @@ class InterceptorInfo: public Struct {
   static const int kDeleterOffset = kQueryOffset + kPointerSize;
   static const int kEnumeratorOffset = kDeleterOffset + kPointerSize;
   static const int kDataOffset = kEnumeratorOffset + kPointerSize;
-  static const int kSize = kDataOffset + kPointerSize;
+  static const int kFlagsOffset = kDataOffset + kPointerSize;
+  static const int kSize = kFlagsOffset + kPointerSize;
+
+  static const int kCanInterceptSymbolsBit = 0;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(InterceptorInfo);