Allow loading custom application shells.

src/main.js

@@ -36,7 +36,17 @@ require.config({
 
         // The file system implementation. Change this value to use different 
         // implementations (e.g. cloud-based storage).
-        "fileSystemImpl"    : "filesystem/impls/appshell/AppshellFileSystem"
+        "fileSystemImpl"    : "filesystem/impls/appshell/AppshellFileSystem",
+
+        // The application shell implementation. Brackets-shell provides an
+        // instance of brackets.app, it will be used and the default value
+        // points to a void implementation. However, when running Brackets in a
+        // different environment, use this to load your implementation. For the
+        // definition of the interface, see appshell.app namespace at
+        // https://github.com/adobe/brackets-shell/blob/master/appshell/appshell_extensions.js
+        // Change this value to load custom implementation to run brackets in
+        // something else than Brackets shell (e.g. in a browser).
+        "appShellImpl"      : "utils/InBrowserShell"
     }
 });
 

src/utils/Global.js

@@ -108,7 +108,7 @@ define(function (require, exports, module) {
 
     // Create empty app namespace if running in-browser
     if (!global.brackets.app) {
-        global.brackets.app = {};
+        global.brackets.app = require("appShellImpl");
     }
 
     // Loading extensions requires creating new require.js contexts, which

src/utils/InBrowserShell.js

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2014 Adobe Systems Incorporated. All rights reserved.
+ *  
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"), 
+ * to deal in the Software without restriction, including without limitation 
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
+ * and/or sell copies of the Software, and to permit persons to whom the 
+ * Software is furnished to do so, subject to the following conditions:
+ *  
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *  
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
+ * DEALINGS IN THE SOFTWARE.
+ * 
+ */
+
+/*jslint vars: true, plusplus: true, devel: true, nomen: true, indent: 4, maxerr: 50 */
+/*global define */
+define(function (require, exports, module) {
+    "use strict";
+
+    // this implementation is intentionally left empty
+    // see src/main.js for details
+
+});