dart2js: fix dependency tracking for deferred loading when types are only used

pkg/compiler/lib/src/deferred_load.dart

Index: pkg/compiler/lib/src/deferred_load.dart
diff --git a/pkg/compiler/lib/src/deferred_load.dart b/pkg/compiler/lib/src/deferred_load.dart
index 3213f9f52dfbaad0b5fd6e5ee88e0e7c20b1916d..92aa9094704093940ddfadfaed6d0a290a0a39e0 100644
--- a/pkg/compiler/lib/src/deferred_load.dart
+++ b/pkg/compiler/lib/src/deferred_load.dart
@@ -280,6 +280,19 @@ class DeferredLoadTask extends CompilerTask {
 
         elements.add(dependency);
       }
+
+      treeElements.forEachType((n, t) {
+        registerTypeArgumentsAsDependencies(type) {

[floitsch, 2015/07/17 09:22:25]

Especially for nested functions I want to have a return type (as it's otherwise
hard to see if it's a function call or not).
It also helps when the argument has a type.

Also one new line before and after nested functions (to make them stick out even
more).

[Siggi Cherem (dart-lang), 2015/07/17 15:34:48]

Done.

+          var dependency = type.element;

[floitsch, 2015/07/17 09:22:25]

We usually don't use "var".

[Siggi Cherem (dart-lang), 2015/07/17 15:34:49]

Done.

+          if (dependency == null || dependency.isTypeVariable) return;
+          elements.add(dependency);
+          if (type is GenericType) {
+            type.typeArguments.forEach(registerTypeArgumentsAsDependencies);
+          }
+        }
+        if (n is NewExpression) registerTypeArgumentsAsDependencies(t);
+      });
+
       treeElements.forEachConstantNode((Node node, _) {
         // Explicitly depend on the backend constants.
         ConstantValue value =