Rename ReceiverMask and ReceiverMaskSet and update comments.

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.js_emitter.program_builder;
 
 import '../js_emitter.dart' show computeMixinClass, Emitter;
 import '../model.dart';
 
 import '../../common.dart';
@@ skipping 12 matching lines @@
     MainCallStubGenerator,
     ParameterStubGenerator,
     RuntimeTypeGenerator,
     TypeTestProperties;
 
 import '../../elements/elements.dart' show
     FieldElement,
     MethodElement,
     ParameterElement;
 
-import '../../universe/universe.dart' show Universe, ReceiverMaskSet;
+import '../../universe/universe.dart' show Universe, SelectorConstraints;
 import '../../deferred_load.dart' show DeferredLoadTask, OutputUnit;
 
 part 'collector.dart';
 part 'registry.dart';
 part 'field_visitor.dart';
 
 /// Builds a self-contained representation of the program that can then be
 /// emitted more easily by the individual emitters.
 class ProgramBuilder {
   final Compiler _compiler;
@@ skipping 334 matching lines @@
     void visitMember(ClassElement enclosing, Element member) {
       assert(invariant(element, member.isDeclaration));
       assert(invariant(element, element == enclosing));
 
       if (Elements.isNonAbstractInstanceMember(member)) {
         // TODO(herhut): Remove once _buildMethod can no longer return null.
         Method method = _buildMethod(member);
         if (method != null) methods.add(method);
       }
       if (member.isGetter || member.isField) {
-        Map<Selector, ReceiverMaskSet> selectors =
+        Map<Selector, SelectorConstraints> selectors =
             _compiler.codegenWorld.invocationsByName(member.name);
         if (selectors != null && !selectors.isEmpty) {
 
           Map<js.Name, js.Expression> callStubsForMember =
               classStubGenerator.generateCallStubsForGetter(member, selectors);
           callStubsForMember.forEach((js.Name name, js.Expression code) {
             callStubs.add(_buildStubMethod(name, code, element: member));
           });
         }
       }
@@ skipping 430 matching lines @@
       Constant constant = new Constant(name, holder, constantValue);
       _constants[constantValue] = constant;
     }
   }
 
   Holder _registerStaticStateHolder() {
     return _registry.registerHolder(
         namer.staticStateHolder, isStaticStateHolder: true);
   }
 }