[inspector] exposed builtins for injected script source

src/inspector/injected_script_externs.js

Index: src/inspector/injected_script_externs.js
diff --git a/src/inspector/injected_script_externs.js b/src/inspector/injected_script_externs.js
index 20e4d24e9c84a1a4865cd941cb65046783aa14e4..43d765f507020ca5aa73bff6a1a9239e4e53c8cb 100644
--- a/src/inspector/injected_script_externs.js
+++ b/src/inspector/injected_script_externs.js
@@ -70,6 +70,37 @@ InjectedScriptHostClass.prototype.bind = function(value, groupName) {}
  */
 InjectedScriptHostClass.prototype.proxyTargetValue = function(object) {}
 
+/**
+ * @param {!Object} obj
+ * @return {!Array<string>}
+ */
+InjectedScriptHostClass.prototype.keys = function(obj) {}
+
+/**
+ * @param {!Object} obj
+ * @return {Object}
+ */
+InjectedScriptHostClass.prototype.getPrototypeOf = function(obj) {}
+
+/**
+ * @param {!Object} obj
+ * @param {string} prop
+ * @return {Object}
+ */
+InjectedScriptHostClass.prototype.getOwnPropertyDescriptor = function(obj, prop) {}
+
+/**
+ * @param {!Object} obj
+ * @return {!Array<string>}
+ */
+InjectedScriptHostClass.prototype.getOwnPropertyNames = function(obj) {}
+
+/**
+ * @param {!Object} obj
+ * @return {!Array<symbol>}
+ */
+InjectedScriptHostClass.prototype.getOwnPropertySymbols = function(obj) {}
+
 /** @type {!InjectedScriptHostClass} */
 var InjectedScriptHost;
 /** @type {!Window} */