Reformat code to reduce churn

pkg/analyzer/lib/source/sdk_ext.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 source.sdk_ext;
 
 import 'dart:convert';
 import 'dart:core' hide Resource;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/java_io.dart' show JavaFile;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart' show FileBasedSource;
 import 'package:path/path.dart' as pathos;
 
 /// Given a packageMap (see [PackageMapProvider]), check in each package's lib
 /// directory for the existence of a `_sdkext` file. This file must contain a
 /// JSON encoded map. Each key in the map is a `dart:` library name. Each value
 /// is a path (relative to the directory containing `_sdkext`) to a dart script
 /// for the given library. For example:
 /// {
 ///   "dart:sky": "../sdk_ext/dart_sky.dart"
 /// }
 ///
 /// If a key doesn't begin with `dart:` it is ignored.
 class SdkExtUriResolver extends UriResolver {
   static const String SDK_EXT_NAME = '_sdkext';
   static const String DART_COLON_PREFIX = 'dart:';
 
-  final Map<String, String> _urlMappings = <String,String>{};
+  final Map<String, String> _urlMappings = <String, String>{};
 
   /// Construct a [SdkExtUriResolver] from a package map
   /// (see [PackageMapProvider]).
   SdkExtUriResolver(Map<String, List<Folder>> packageMap) {
     if (packageMap == null) {
       return;
     }
     packageMap.forEach(_processPackage);
   }
 
   /// Number of sdk extensions.
   int get length => _urlMappings.length;
 
   /// Return the path mapping for [libName] or null if there is none.
-  String operator[](String libName) => _urlMappings[libName];
+  String operator [](String libName) => _urlMappings[libName];
 
   /// Programmatically add a new SDK extension given a JSON description
   /// ([sdkExtJSON]) and a lib directory ([libDir]).
   void addSdkExt(String sdkExtJSON, Folder libDir) {
     _processSdkExt(sdkExtJSON, libDir);
   }
 
   @override
   Source resolveAbsolute(Uri importUri, [Uri actualUri]) {
     String libraryName = _libraryName(importUri);
@@ skipping 118 matching lines @@
   /// Resolve a 'part' statement inside an sdk extension.
   Source _resolvePart(Uri libraryEntry, String partPath, Uri importUri) {
     // Library part.
     var directory = pathos.dirname(libraryEntry.path);
     var partUri = new Uri.file(pathos.join(directory, partPath));
     assert(partUri.isAbsolute);
     JavaFile javaFile = new JavaFile.fromUri(partUri);
     return new FileBasedSource(javaFile, importUri);
   }
 }