Add JSC utility header to RCTBridge

Reviewed By: shergin

Differential Revision: D4823509

fbshipit-source-id: 79c96d3bc183d89a5dec7da06b0a0a710d8c7dea

React/Base/RCTBridge+JavaScriptCore.h

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <JavaScriptCore/JavaScriptCore.h>
+
+#import <React/RCTBridge.h>
+
+@interface RCTBridge (JavaScriptCore)
+
+/**
+ * The JSContext used by the bridge.
+ */
+@property (nonatomic, readonly, strong) JSContext *jsContext;
+
+/**
+ * The raw JSGlobalContextRef used by the bridge.
+ */
+@property (nonatomic, readonly, assign) JSGlobalContextRef jsContextRef;
+
+@end