fix(errors): require passing stack traces explicitly in ng2 own code

modules/angular2/test/core/compiler/integration_dart_spec.dart

@@ -7,6 +7,7 @@ import 'package:angular2/src/test_lib/test_bed.dart';
 import 'package:angular2/test_lib.dart';
 
 class MockException implements Error { var message; var stackTrace; }
+class NonError { var message; }
 
 void functionThatThrows() {
   try { throw new MockException(); }
@@ -19,6 +20,16 @@ void functionThatThrows() {
   }
 }
 
+void functionThatThrowsNonError() {
+  try { throw new NonError(); }
+  catch(e, stack) {
+    // If we lose the stack trace the message will no longer match
+    // the first line in the stack
+    e.message = stack.toString().split('\n')[0];
+    rethrow;
+  }
+}
+
 main() {
   describe('TypeLiteral', () {
     it('should publish via appInjector',
@@ -37,7 +48,7 @@ main() {
   });
 
   describe('Error handling', () {
-    it('should preserve stack traces throws from components',
+    it('should preserve Error stack traces thrown from components',
         inject([TestBed, AsyncTestCompleter], (tb, async) {
       tb.overrideView(Dummy, new View(
         template: '<throwing-component></throwing-component>',
@@ -49,6 +60,19 @@ main() {
         async.done();
       });
     }));
+
+    it('should preserve non-Error stack traces thrown from components',
+        inject([TestBed, AsyncTestCompleter], (tb, async) {
+      tb.overrideView(Dummy, new View(
+        template: '<throwing-component2></throwing-component2>',
+        directives: [ThrowingComponent2]
+      ));
+
+      tb.createView(Dummy).catchError((e, stack) {
+        expect(stack.toString().split('\n')[0]).toEqual(e.message);
+        async.done();
+      });
+    }));
   });
 }
 
@@ -81,3 +105,13 @@ class ThrowingComponent {
     functionThatThrows();
   }
 }
+
+@Component(
+  selector: 'throwing-component2'
+)
+@View(template: '')
+class ThrowingComponent2 {
+  ThrowingComponent2() {
+    functionThatThrowsNonError();
+  }
+}