[Policy] Implement view decorator

Implement policy-driven view decorator, sufficient to satisfy
specs. WTD-1062.

platform/policy/bundle.json

@@ -10,6 +10,12 @@
                 "implementation": "PolicyActionDecorator.js",
                 "depends": [ "policyService" ]
             },
+            {
+                "type": "decorator",
+                "provides": "viewService",
+                "implementation": "PolicyViewDecorator.js",
+                "depends": [ "policyService" ]
+            },
             {
                 "type": "provider",
                 "provides": "policyService",

platform/policy/src/PolicyActionDecorator.js

@@ -15,7 +15,7 @@ define(
             return {
                 /**
                  * Get actions which are applicable in this context.
-                 * These will be filters to remove any actions which
+                 * These will be filtered to remove any actions which
                  * are deemed inapplicable by policy.
                  * @param context the context in which the action will occur
                  * @returns {Action[]} applicable actions

platform/policy/src/PolicyViewDecorator.js

@@ -0,0 +1,37 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        /**
+         * Filters out views based on policy.
+         * @param {PolicyService} policyService the service which provides
+         *        policy decisions
+         * @param {ViewService} viewService the service to decorate
+         */
+        function PolicyActionDecorator(policyService, viewService) {
+            return {
+                /**
+                 * Get views which are applicable to this domain object.
+                 * These will be filtered to remove any views which
+                 * are deemed inapplicable by policy.
+                 * @param {DomainObject} the domain object to view
+                 * @returns {View[]} applicable views
+                 */
+                getViews: function (domainObject) {
+                    // Check if an action is allowed by policy.
+                    function allow(view) {
+                        return policyService.allow('view', view, domainObject);
+                    }
+
+                    // Look up actions, filter out the disallowed ones.
+                    return viewService.getViews(domainObject).filter(allow);
+                }
+            };
+        }
+
+        return PolicyActionDecorator;
+    }
+);

platform/policy/test/PolicyViewDecoratorSpec.js

@@ -54,7 +54,7 @@ define(
             it("provides views from its decorated view service", function () {
                 // Mock policy service allows everything by default,
                 // so everything should be returned
-                expect(decorator.getActions(mockDomainObject))
+                expect(decorator.getViews(mockDomainObject))
                     .toEqual(testViews);
             });