Verify files have BOM during publish task

This verification is designed to simulate part of the Windows App
Certification Kit test.

Protects us from regressing #1315 in the future.

tasks/check-bom.js

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved. Licensed under the MIT License. See License.txt in the project root for license information.
+(function () {
+    "use strict";
+
+    module.exports = function (grunt) {
+
+        // Verifies that files begin with a UTF8 BOM. Files without one will not be able to pass the
+        // Windows App Certification Kit test.
+
+        grunt.registerMultiTask("check-bom", function () {
+            function checkBom(filePath) {
+                if (grunt.file.exists(filePath)) {
+                    var content = grunt.file.read(filePath, { encoding: null });
+                    if (content.length < 3 || content[0] !== 0xef || content[1] !== 0xbb || content[2] !== 0xbf) {
+                        grunt.fail.fatal("check-bom File is missing BOM: " + filePath);
+                    }
+                } else {
+                    grunt.log.warn("check-bom No such file: " + filePath);
+                }
+            }
+
+            this.filesSrc.forEach(checkBom);
+        });
+
+    };
+})();

tasks/options/check-bom.js

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved. Licensed under the MIT License. See License.txt in the project root for license information.
+(function () {
+    "use strict";
+
+    var config = require("../../config.js");
+
+    function searchDirectory(directoryPath) {
+        return {
+            cwd: directoryPath,
+            src: "**/*.+(js|css|htm|html)",
+            expand: true,
+            nocase: true
+        };
+    }
+
+    module.exports = {
+        publishWinJs: {
+            files: [
+                searchDirectory(config.winjsPublishRoot),
+                searchDirectory(config.winjsBowerRepo)
+            ]
+        },
+        publishLocalization: {
+            files: [
+                searchDirectory(config.localizationPublishRoot),
+                searchDirectory(config.localizationBowerRepo)
+            ]
+        }
+    };
+})();

tasks/publish.js

@@ -16,10 +16,12 @@
             // winjs
             'gitreset:publishWinJsBower', 'gitclean:publishWinJsBower', 'gitpull:publishWinJsBower', // Make the local bower repo match the one on GitHub
             'clean:publishWinJs', 'copy:publishWinJs', 'compress:publishWinJs', 'gitadd:publishWinJsBower', 'nugetpack:publishWinJs',
+            'check-bom:publishWinJs', // BOM verification should be the last task in the group
 
             // winjs-localization
             'gitreset:publishLocalizationBower', 'gitclean:publishLocalizationBower', 'gitpull:publishLocalizationBower', // Make the local bower repo match the one on GitHub
-            'clean:publishLocalization', 'copy:publishLocalization', 'compress:publishLocalization', 'gitadd:publishLocalizationBower', 'nugetpack:publishLocalization'
+            'clean:publishLocalization', 'copy:publishLocalization', 'compress:publishLocalization', 'gitadd:publishLocalizationBower', 'nugetpack:publishLocalization',
+            'check-bom:publishLocalization' // BOM verification should be the last task in the group
         ]);
 
         // Populates the 'dist' folder and then uses it to: