Start inferring return types for static functions

tests/compiler/dart2js/return_type_inferer_test.dart

Index: tests/compiler/dart2js/return_type_inferer_test.dart
diff --git a/tests/compiler/dart2js/call_site_type_inferer_static_test.dart b/tests/compiler/dart2js/return_type_inferer_test.dart
similarity index 73%
copy from tests/compiler/dart2js/call_site_type_inferer_static_test.dart
copy to tests/compiler/dart2js/return_type_inferer_test.dart
index 3a3a7dd85915788b740f4368b19b576e9d6d58f5..cc83fb1cd45c592bdfd3572dacefa87c9119ae94 100644
--- a/tests/compiler/dart2js/call_site_type_inferer_static_test.dart
+++ b/tests/compiler/dart2js/return_type_inferer_test.dart
@@ -70,30 +70,26 @@ final String TEST_TEN = @"""
   main() { f(1); g(f); }
 """;
 
-void runTest(String test, [List<HType> expectedTypes = null]) {
+void runTest(String test, [HType expectedType = HType.UNKNOWN]) {
   compileAndFind(
     test,
     'f',
     (backend, x) {
-      List<HType> types =
-          backend.optimisticParameterTypesWithRecompilationOnTypeChange(x);
-      if (expectedTypes != null) {
-        Expect.listEquals(expectedTypes, types);
-      } else {
-        Expect.isNull(types);
-      }
+      HType type =
+          backend.optimisticReturnTypesWithRecompilationOnTypeChange(null, x);
+      Expect.equals(expectedType, type);
   });
 }
 
 void test() {
-  runTest(TEST_ONE, [HType.STRING]);
-  runTest(TEST_TWO, [HType.INTEGER]);
-  runTest(TEST_THREE, [HType.INTEGER]);
-  runTest(TEST_FOUR, [HType.DOUBLE]);
-  runTest(TEST_FIVE, [HType.NUMBER]);
-  runTest(TEST_SIX, [HType.NUMBER]);
+  runTest(TEST_ONE, HType.STRING);
+  runTest(TEST_TWO, HType.INTEGER);
+  runTest(TEST_THREE, HType.INTEGER);
+  runTest(TEST_FOUR, HType.DOUBLE);
+  runTest(TEST_FIVE, HType.NUMBER);
+  runTest(TEST_SIX, HType.NUMBER);
   runTest(TEST_SEVEN);
-  runTest(TEST_EIGHT, [HType.INTEGER, HType.UNKNOWN]);
+  runTest(TEST_EIGHT, HType.INTEGER);
   runTest(TEST_NINE);
   runTest(TEST_TEN);
 }