Rename the global inference task and reduce it's API surface by introducing the

tests/compiler/dart2js/simple_inferrer_closure_test.dart

Index: tests/compiler/dart2js/simple_inferrer_closure_test.dart
diff --git a/tests/compiler/dart2js/simple_inferrer_closure_test.dart b/tests/compiler/dart2js/simple_inferrer_closure_test.dart
index 9eaefa20295c87889d891b278d1875f4d6384042..e9fc5176a1097e2216c3213c57494597a8f96376 100644
--- a/tests/compiler/dart2js/simple_inferrer_closure_test.dart
+++ b/tests/compiler/dart2js/simple_inferrer_closure_test.dart
@@ -119,7 +119,7 @@ void main() {
   Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(TEST, uri);
   asyncTest(() => compiler.run(uri).then((_) {
-    var typesInferrer = compiler.typesTask.typesInferrer;
+    var typesInferrer = compiler.globalInference.typesInferrer;
 
     checkReturn(String name, type) {
       var element = findElement(compiler, name);
@@ -128,16 +128,16 @@ void main() {
           name);
     }
 
-    checkReturn('returnInt1', compiler.typesTask.uint31Type);
-    checkReturn('returnInt2', compiler.typesTask.uint31Type);
-    checkReturn('returnInt3', compiler.typesTask.uint31Type);
-    checkReturn('returnInt4', compiler.typesTask.uint31Type);
-    checkReturn('returnIntOrNull', compiler.typesTask.uint31Type.nullable());
+    checkReturn('returnInt1', compiler.commonMasks.uint31Type);
+    checkReturn('returnInt2', compiler.commonMasks.uint31Type);
+    checkReturn('returnInt3', compiler.commonMasks.uint31Type);
+    checkReturn('returnInt4', compiler.commonMasks.uint31Type);
+    checkReturn('returnIntOrNull', compiler.commonMasks.uint31Type.nullable());
 
-    checkReturn('returnDyn1', compiler.typesTask.dynamicType.nonNullable());
-    checkReturn('returnDyn2', compiler.typesTask.dynamicType.nonNullable());
-    checkReturn('returnDyn3', compiler.typesTask.dynamicType.nonNullable());
-    checkReturn('returnNum1', compiler.typesTask.numType);
+    checkReturn('returnDyn1', compiler.commonMasks.dynamicType.nonNullable());
+    checkReturn('returnDyn2', compiler.commonMasks.dynamicType.nonNullable());
+    checkReturn('returnDyn3', compiler.commonMasks.dynamicType.nonNullable());
+    checkReturn('returnNum1', compiler.commonMasks.numType);
 
     checkReturnInClass(String className, String methodName, type) {
       var cls = findElement(compiler, className);