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

tests/compiler/dart2js/type_inference7_test.dart

Index: tests/compiler/dart2js/type_inference7_test.dart
diff --git a/tests/compiler/dart2js/type_inference7_test.dart b/tests/compiler/dart2js/type_inference7_test.dart
index 072d42d7aed58f9bc408b1a4bba7dd016f4c89e5..af867ccc6f615f0c6b16ba008c4fc24fc70a16d9 100644
--- a/tests/compiler/dart2js/type_inference7_test.dart
+++ b/tests/compiler/dart2js/type_inference7_test.dart
@@ -23,19 +23,19 @@ Future runTest() async {
     // Assertions enabled:
     var compiler = compilerFor(TEST, uri, enableUserAssertions: true);
     await compiler.run(uri);
-    var typesTask = compiler.typesTask;
-    var typesInferrer = typesTask.typesInferrer;
+    var commonMasks = compiler.commonMasks;
+    var typesInferrer = compiler.globalInference.typesInferrer;
     var foo = findElement(compiler, "foo");
     // Return type is null|bool.
     var mask = typesInferrer.getReturnTypeOfElement(foo);
     Expect.isTrue(mask.isNullable);
-    Expect.equals(typesTask.boolType, simplify(mask.nonNullable(), compiler));
+    Expect.equals(commonMasks.boolType, simplify(mask.nonNullable(), compiler));
     // First parameter is uint31|String|bool.
     var mask1 = typesInferrer.getTypeOfElement(foo.parameters[0]);
     Expect.isTrue(mask1.isUnion);
-    var expectedTypes = new Set.from([typesTask.uint31Type,
-                                      typesTask.stringType,
-                                      typesTask.boolType]);
+    var expectedTypes = new Set.from([commonMasks.uint31Type,
+                                      commonMasks.stringType,
+                                      commonMasks.boolType]);
     for (var typeMask in mask1.disjointMasks) {
       Expect.isFalse(typeMask.isNullable);
       var simpleType = simplify(typeMask, compiler);
@@ -45,15 +45,16 @@ Future runTest() async {
     // Second parameter is bool or null.
     var mask2 = typesInferrer.getTypeOfElement(foo.parameters[1]);
     Expect.isTrue(mask2.isNullable);
-    Expect.equals(typesTask.boolType, simplify(mask2.nonNullable(), compiler));
+    Expect.equals(
+        commonMasks.boolType, simplify(mask2.nonNullable(), compiler));
   }
 
   {
     // Assertions disabled:
     var compiler = compilerFor(TEST, uri, enableUserAssertions: false);
     await compiler.run(uri);
-    var typesTask = compiler.typesTask;
-    var typesInferrer = typesTask.typesInferrer;
+    var commonMasks = compiler.commonMasks;
+    var typesInferrer = compiler.globalInference.typesInferrer;
     var foo = findElement(compiler, "foo");
     // Return type is null.
     var mask = typesInferrer.getReturnTypeOfElement(foo);
@@ -62,7 +63,7 @@ Future runTest() async {
     // First parameter is uint31.
     var mask1 = typesInferrer.getTypeOfElement(foo.parameters[0]);
     Expect.isFalse(mask1.isNullable);
-    Expect.equals(typesTask.uint31Type, simplify(mask1, compiler));
+    Expect.equals(commonMasks.uint31Type, simplify(mask1, compiler));
     // Second parameter is null.
     var mask2 = typesInferrer.getTypeOfElement(foo.parameters[1]);
     Expect.isTrue(mask2.isNullable);