[Views] Warn if view omits key

Warn if a view definition does not include a key,
and prune it from the list of views. This avoids
an underlying cause of WTD-628, which is fixed for
plots specifically in the previous commit but could
recur if other views were to omit keys.

platform/core/bundle.json

@@ -67,7 +67,7 @@
                 "provides": "viewService",
                 "type": "provider",
                 "implementation": "views/ViewProvider.js",
-                "depends": [ "views[]" ]
+                "depends": [ "views[]", "$log" ]
             }
         ],
         "types": [

platform/core/src/views/ViewProvider.js

@@ -37,7 +37,25 @@ define(
          * @constructor
          * @param {View[]} an array of view definitions
          */
-        function ViewProvider(views) {
+        function ViewProvider(views, $log) {
+
+            // Views without defined keys cannot be used in the user
+            // interface, and can result in unexpected behavior. These
+            // are filtered out using this function.
+            function validate(view) {
+                var key = view.key;
+
+                // Leave a log message to support detection of this issue.
+                if (!key) {
+                    $log.warn([
+                        "No key specified for view in ",
+                        (view.bundle || {}).path,
+                        "; omitting this view."
+                    ].join(""));
+                }
+
+                return key;
+            }
 
             // Check if an object has all capabilities designated as `needs`
             // for a view. Exposing a capability via delegation is taken to
@@ -79,6 +97,9 @@ define(
                 });
             }
 
+            // Filter out any key-less views
+            views = views.filter(validate);
+
             return {
                 /**
                  * Get all views which are applicable to this domain object.

platform/core/test/views/ViewProviderSpec.js

@@ -25,6 +25,7 @@ define(
                 delegates = {},
                 delegation,
                 mockDomainObject = {},
+                mockLog,
                 provider;
 
             beforeEach(function () {
@@ -38,6 +39,7 @@ define(
                 mockDomainObject.useCapability = function (c, v) {
                     return capabilities[c] && capabilities[c].invoke(v);
                 };
+                mockLog = jasmine.createSpyObj("$log", ["warn", "info", "debug"]);
 
                 capabilities = {};
                 delegates = {};
@@ -48,7 +50,7 @@ define(
                     }
                 };
 
-                provider = new ViewProvider([viewA, viewB, viewC]);
+                provider = new ViewProvider([viewA, viewB, viewC], mockLog);
             });
 
             it("reports views provided as extensions", function () {
@@ -71,6 +73,20 @@ define(
                     .toEqual([viewA, viewC]);
             });
 
+            it("warns if keys are omitted from views", function () {
+                // Verify that initial construction issued no warning
+                expect(mockLog.warn).not.toHaveBeenCalled();
+                // Recreate with no keys; that view should be filtered out
+                expect(
+                    new ViewProvider(
+                        [viewA, { some: "bad view" }],
+                        mockLog
+                    ).getViews(mockDomainObject)
+                ).toEqual([viewA]);
+                // We should have also received a warning, to support debugging
+                expect(mockLog.warn).toHaveBeenCalledWith(jasmine.any(String));
+            });
+
         });
     }
 );