expose strong checker API, for use by analyzer_cli

lib/src/utils.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.
 
 /// Holds a couple utility functions used at various places in the system.
 library dev_compiler.src.utils;
 
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
@@ skipping 61 matching lines @@
   if (result.startsWith(new RegExp('[0-9]')) || invalidVariableName(result)) {
     return '\$$result';
   }
   return result;
 }
 
 // Invalid characters for identifiers, which would need to be escaped.
 final _invalidCharInIdentifier = new RegExp(r'[^A-Za-z_$0-9]');
 
 /// Returns all libraries transitively imported or exported from [start].
-Iterable<LibraryElement> reachableLibraries(LibraryElement start) {
+List<LibraryElement> reachableLibraries(LibraryElement start) {
   var results = <LibraryElement>[];
   var seen = new Set();
   void find(LibraryElement lib) {
     if (seen.contains(lib)) return;
     seen.add(lib);
     results.add(lib);
     lib.importedLibraries.forEach(find);
     lib.exportedLibraries.forEach(find);
   }
   find(start);
@@ skipping 369 matching lines @@
       lineInfo.getLocation(++lineEnd).lineNumber == lineNum);
 
   var text = content.substring(start, end);
   var lineText = content.substring(lineStart, lineEnd);
   return new SourceSpanWithContext(startLoc, endLoc, text, lineText);
 }
 
 bool isInlineJS(Element e) => e is FunctionElement &&
     e.library.source.uri.toString() == 'dart:_foreign_helper' &&
     e.name == 'JS';