[Stylesheets] Add spec, docs

Add tests and JSDoc to the style sheet loader introduced to
allow bundles to introduce their own CSS files through the
platform's regular extension mechanism; WTD-591.

platform/commonUI/general/test/StyleSheetLoaderSpec.js

@@ -0,0 +1,57 @@
+/*global define,Promise,describe,it,expect,beforeEach,waitsFor,jasmine*/
+
+define(
+    ["../src/StyleSheetLoader"],
+    function (StyleSheetLoader) {
+        "use strict";
+
+        describe("The style sheet loader", function () {
+            var testStyleSheets,
+                mockDocument,
+                mockPlainDocument,
+                mockHead,
+                mockElement,
+                loader;
+
+            beforeEach(function () {
+                var testBundle = {
+                    path: "a/b",
+                    resources: "c"
+                };
+
+                testStyleSheets = [
+                    { stylesheetUrl: "d.css", bundle: testBundle },
+                    { stylesheetUrl: "e.css", bundle: testBundle },
+                    { stylesheetUrl: "f.css", bundle: testBundle }
+                ];
+
+                mockPlainDocument =
+                    jasmine.createSpyObj("document", ["createElement"]);
+                mockDocument = [ mockPlainDocument ];
+                mockDocument.find = jasmine.createSpy("$document.find");
+                mockHead = jasmine.createSpyObj("head", ["append"]);
+                mockElement = jasmine.createSpyObj("link", ["setAttribute"]);
+
+                mockDocument.find.andReturn(mockHead);
+                mockPlainDocument.createElement.andReturn(mockElement);
+
+                loader = new StyleSheetLoader(testStyleSheets, mockDocument);
+            });
+
+            it("appends one link per stylesheet extension", function () {
+                expect(mockHead.append.calls.length)
+                    .toEqual(testStyleSheets.length);
+            });
+
+            it("appends links to the head", function () {
+                expect(mockDocument.find).toHaveBeenCalledWith('head');
+            });
+
+            it("adjusts link locations", function () {
+                expect(mockElement.setAttribute)
+                    .toHaveBeenCalledWith('href', "a/b/c/d.css");
+            });
+        });
+    }
+);
+

platform/commonUI/general/test/suite.json

@@ -9,5 +9,6 @@
     "controllers/ViewSwitcherController",
     "directives/MCTContainer",
     "directives/MCTDrag",
-    "directives/MCTResize"
+    "directives/MCTResize",
+    "StyleSheetLoader"
 ]