[api] Expose ES6 7.3.14 SetIntegrityLevel on v8::Object

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 7952fc9bd1e1b9b9cb5d85c920dee149582ff4ad..9643acc005b21f66c5aa52e531e1078b9a78f3d8 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -2639,6 +2639,10 @@ enum AccessControl {
   PROHIBITS_OVERWRITING = 1 << 2
 };
 
+/**
+ * Integrity level for objects.
+ */
+enum class IntegrityLevel { kFrozen, kSealed };
 
 /**
  * A JavaScript object (ECMA-262, 4.3.3)
@@ -2830,6 +2834,11 @@ class V8_EXPORT Object : public Value {
    */
   Local<String> GetConstructorName();
 
+  /**
+   * Sets the integrity level of the object.
+   */
+  Maybe<bool> SetIntegrityLevel(Local<Context> context, IntegrityLevel level);
+
   /** Gets the number of internal fields for this Object. */
   int InternalFieldCount();