Refactor PrivateScriptRunner.js to reduce the number of globally exposed variables

Source/bindings/core/v8/PrivateScriptRunner.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
-// This list must be in sync with the enum in ExceptionCode.h.  The order matters.
-var domExceptions = [
-    "IndexSizeError",
-    "HierarchyRequestError",
-    "WrongDocumentError",
-    "InvalidCharacterError",
-    "NoModificationAllowedError",
-    "NotFoundError",
-    "NotSupportedError",
-    "InUseAttributeError", // Historical. Only used in setAttributeNode etc which have been removed from the DOM specs.
-
-    // Introduced in DOM Level 2:
-    "InvalidStateError",
-    "SyntaxError",
-    "InvalidModificationError",
-    "NamespaceError",
-    "InvalidAccessError",
-
-    // Introduced in DOM Level 3:
-    "TypeMismatchError", // Historical; use TypeError instead
-
-    // XMLHttpRequest extension:
-    "SecurityError",
-
-    // Others introduced in HTML5:
-    "NetworkError",
-    "AbortError",
-    "URLMismatchError",
-    "QuotaExceededError",
-    "TimeoutError",
-    "InvalidNodeTypeError",
-    "DataCloneError",
-
-    // These are IDB-specific.
-    "UnknownError",
-    "ConstraintError",
-    "DataError",
-    "TransactionInactiveError",
-    "ReadOnlyError",
-    "VersionError",
-
-    // File system
-    "NotReadableError",
-    "EncodingError",
-    "PathExistsError",
-
-    // SQL
-    "SQLDatabaseError", // Naming conflict with DatabaseError class.
-
-    // Web Crypto
-    "OperationError",
-];
-
+var installedClasses = {};
 var domExceptionCode = {};
-var installedClasses = {};
-
-function init()
-{
-    var code = 1;
-    domExceptions.forEach(function (exception) {
-        domExceptionCode[exception] = code;
-        code++;
-    });
-}
 
 function DOMExceptionInPrivateScript(code, message)
 {
     this.code = domExceptionCode[code] || 0;
     this.message = message;
     this.name = "DOMExceptionInPrivateScript";
 }
 
-function privateScriptClass()
-{
-}
-
 function installClass(className, implementation)
 {
+    function privateScriptClass()
+    {
+    }
+
     if (!(className in installedClasses))
         installedClasses[className] = new privateScriptClass();
-    implementation(window, installedClasses[className]);
+    implementation(installedClasses[className]);
 }
 
-init();
+(function (global) {
+    // This list must be in sync with the enum in ExceptionCode.h. The order matters.
+    var domExceptions = [
+        "IndexSizeError",
+        "HierarchyRequestError",
+        "WrongDocumentError",
+        "InvalidCharacterError",
+        "NoModificationAllowedError",
+        "NotFoundError",
+        "NotSupportedError",
+        "InUseAttributeError", // Historical. Only used in setAttributeNode etc which have been removed from the DOM specs.
+
+        // Introduced in DOM Level 2:
+        "InvalidStateError",
+        "SyntaxError",
+        "InvalidModificationError",
+        "NamespaceError",
+        "InvalidAccessError",
+
+        // Introduced in DOM Level 3:
+        "TypeMismatchError", // Historical; use TypeError instead
+
+        // XMLHttpRequest extension:
+        "SecurityError",
+
+        // Others introduced in HTML5:
+        "NetworkError",
+        "AbortError",
+        "URLMismatchError",
+        "QuotaExceededError",
+        "TimeoutError",
+        "InvalidNodeTypeError",
+        "DataCloneError",
+
+        // These are IDB-specific.
+        "UnknownError",
+        "ConstraintError",
+        "DataError",
+        "TransactionInactiveError",
+        "ReadOnlyError",
+        "VersionError",
+
+        // File system
+        "NotReadableError",
+        "EncodingError",
+        "PathExistsError",
+
+        // SQL
+        "SQLDatabaseError", // Naming conflict with DatabaseError class.
+
+        // Web Crypto
+        "OperationError",
+    ];
+
+    var code = 1;
+    domExceptions.forEach(function (exception) {
+        global.domExceptionCode[exception] = code;
+        code++;
+    });
+})(window);
 
 // This line must be the last statement of this JS file.
 // A parenthesis is needed, because the caller of this script (PrivateScriptRunner.cpp)
 // is depending on the completion value of this script.
 (installedClasses);