Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

pkg/compiler/lib/src/ssa/types.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of ssa;
-
-class TypeMaskFactory {
-  static TypeMask fromInferredType(TypeMask mask, Compiler compiler) {
-    JavaScriptBackend backend = compiler.backend;
-    if (mask == null) return backend.dynamicType;
-    return mask;
-  }
-
-  static TypeMask inferredReturnTypeForElement(
-      Element element, Compiler compiler) {
-    return fromInferredType(
-        compiler.typesTask.getGuaranteedReturnTypeOfElement(element),
-        compiler);
-  }
-
-  static TypeMask inferredTypeForElement(Element element, Compiler compiler) {
-    return fromInferredType(
-        compiler.typesTask.getGuaranteedTypeOfElement(element),
-        compiler);
-  }
-
-  static TypeMask inferredTypeForSelector(Selector selector, Compiler compiler) {
-    return fromInferredType(
-        compiler.typesTask.getGuaranteedTypeOfSelector(selector),
-        compiler);
-  }
-
-  static TypeMask inferredForNode(Element owner, ast.Node node,
-                                  Compiler compiler) {
-    return fromInferredType(
-        compiler.typesTask.getGuaranteedTypeOfNode(owner, node),
-        compiler);
-  }
-
-  static TypeMask fromNativeBehavior(native.NativeBehavior nativeBehavior,
-                                     Compiler compiler) {
-    ClassWorld classWorld = compiler.world;
-    JavaScriptBackend backend = compiler.backend;
-    if (nativeBehavior.typesReturned.isEmpty) return backend.dynamicType;
-
-    TypeMask result = nativeBehavior.typesReturned
-        .map((type) => fromNativeType(type, compiler))
-        .reduce((t1, t2) => t1.union(t2, classWorld));
-    assert(!(result.isEmpty && !result.isNullable));
-    return result;
-  }
-
-  // [type] is either an instance of [DartType] or special objects
-  // like [native.SpecialType.JsObject].
-  static TypeMask fromNativeType(type, Compiler compiler) {
-    ClassWorld classWorld = compiler.world;
-    JavaScriptBackend backend = compiler.backend;
-    if (type == native.SpecialType.JsObject) {
-      return new TypeMask.nonNullExact(compiler.objectClass, classWorld);
-    } else if (type.isVoid) {
-      return backend.nullType;
-    } else if (type.element == compiler.nullClass) {
-      return backend.nullType;
-    } else if (type.treatAsDynamic) {
-      return backend.dynamicType;
-    } else {
-      return new TypeMask.nonNullSubtype(type.element, classWorld);
-    }
-  }
-}