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

pkg/compiler/lib/src/js_backend/no_such_method_registry.dart

 // Copyright (c) 2015, 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.
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers, Names, Selectors;
 import '../compiler.dart' show Compiler;
 import '../elements/elements.dart';
 import '../tree/tree.dart';
 import '../types/types.dart';
@@ skipping 107 matching lines @@
 
   /// Returns [true] if the given element is a complex [noSuchMethod]
   /// implementation. An implementation is complex if it falls into
   /// category D, as described above.
   bool isComplex(FunctionElement element) {
     assert(element.name == Identifiers.noSuchMethod_);
     return otherImpls.contains(element);
   }
 
   _subcategorizeOther(FunctionElement element) {
-    TypeMask returnType =
-        _compiler.typesTask.getGuaranteedReturnTypeOfElement(element);
-    if (returnType == const TypeMask.nonNullEmpty()) {
+    if (_compiler.globalInference.throwsAlways(element)) {
       complexNoReturnImpls.add(element);
     } else {
       complexReturningImpls.add(element);
     }
   }
 
   NsmCategory _categorizeImpl(FunctionElement element) {
     assert(element.name == Identifiers.noSuchMethod_);
     if (defaultImpls.contains(element)) {
       return NsmCategory.DEFAULT;
@@ skipping 123 matching lines @@
       if (body.statements.nodes.head is ExpressionStatement) {
         ExpressionStatement stmt = body.statements.nodes.head;
         return stmt.expression is Throw;
       }
     }
     return false;
   }
 }
 
 enum NsmCategory { DEFAULT, THROWING, NOT_APPLICABLE, OTHER, }