Fix context comparisons

pkg/analyzer/lib/file_system/memory_file_system.dart

Index: pkg/analyzer/lib/file_system/memory_file_system.dart
diff --git a/pkg/analyzer/lib/file_system/memory_file_system.dart b/pkg/analyzer/lib/file_system/memory_file_system.dart
index 5d4e67501c80abebbd9cfb35396f58e850c86380..a69e15eabd5820e2e34ef7da86da0e5e05ed411b 100644
--- a/pkg/analyzer/lib/file_system/memory_file_system.dart
+++ b/pkg/analyzer/lib/file_system/memory_file_system.dart
@@ -50,7 +50,7 @@ class MemoryResourceProvider implements ResourceProvider {
    * this class are never converted automatically.
    */
   String convertPath(String path) {
-    if (pathContext == pathos.windows &&
+    if (pathContext.style == pathos.windows.style &&
         path.startsWith(pathos.posix.separator)) {
       path = r'C:' +
           path.replaceAll(pathos.posix.separator, pathos.windows.separator);
@@ -341,10 +341,6 @@ class _MemoryDummyLink extends _MemoryResource implements File {
   }
 
   @override
-  Uri toUri() =>
-      new Uri.file(path, windows: _provider.pathContext == pathos.windows);
-
-  @override
   void writeAsBytesSync(List<int> bytes) {
     throw new FileSystemException(path, 'File could not be written');
   }