Rename apiimpl.Compiler to CompilerImpl.

tests/compiler/dart2js/analyze_dart2js_helpers_test.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.
 
 library dart2js.analyze_helpers.test;
 
 import 'dart:io';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/compiler_new.dart' show
     Diagnostic;
 import 'package:compiler/src/apiimpl.dart' show
-    Compiler;
+    CompilerImpl;
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/constants/expressions.dart' show
     ConstructedConstantExpression;
 import 'package:compiler/src/dart_types.dart' show
     InterfaceType;
 import 'package:compiler/src/diagnostics/source_span.dart' show
     SourceSpan;
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/filenames.dart' show
     nativeToUriPath;
@@ skipping 13 matching lines @@
   bool verbose = arguments.contains('-v');
 
   List<String> options = <String>[
     Flags.analyzeOnly,
     Flags.analyzeMain,
     '--categories=Client,Server'];
   if (verbose) {
     options.add(Flags.verbose);
   }
   asyncTest(() async {
-    Compiler compiler = compilerFor(
+    CompilerImpl compiler = compilerFor(
         options: options, showDiagnostics: verbose);
     FormattingDiagnosticHandler diagnostics =
         new FormattingDiagnosticHandler(compiler.provider);
     HelperAnalyzer analyzer = new HelperAnalyzer(diagnostics);
     Directory dir =
         new Directory.fromUri(Uri.base.resolve('pkg/compiler/lib/'));
     for (FileSystemEntity entity in dir.listSync(recursive: true)) {
       if (entity is File && entity.path.endsWith('.dart')) {
         Uri file = Uri.base.resolve(nativeToUriPath(entity.path));
         if (verbose) {
@@ skipping 169 matching lines @@
   }
 
   @override
   void visitConstConstructorInvoke(
       NewExpression node,
       ConstructedConstantExpression constant,
       _) {
     checkAccess(node, constant.target);
   }
 }