Change File.directory to not do any IO

runtime/bin/file.h

 // Copyright (c) 2013, 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.
 
 #ifndef BIN_FILE_H_
 #define BIN_FILE_H_
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ skipping 49 matching lines @@
     kSocket = 3,
     kOther = 4
   };
 
   enum FileRequest {
     kExistsRequest = 0,
     kCreateRequest = 1,
     kDeleteRequest = 2,
     kOpenRequest = 3,
     kFullPathRequest = 4,
-    kDirectoryRequest = 5,
-    kCloseRequest = 6,
-    kPositionRequest = 7,
-    kSetPositionRequest = 8,
-    kTruncateRequest = 9,
-    kLengthRequest = 10,
-    kLengthFromPathRequest = 11,
-    kLastModifiedRequest = 12,
-    kFlushRequest = 13,
-    kReadByteRequest = 14,
-    kWriteByteRequest = 15,
-    kReadRequest = 16,
-    kReadIntoRequest = 17,
-    kWriteFromRequest = 18,
-    kCreateLinkRequest = 19,
-    kDeleteLinkRequest = 20,
-    kLinkTargetRequest = 21,
-    kTypeRequest = 22,
-    kIdenticalRequest = 23,
-    kStatRequest = 24
+    kCloseRequest = 5,
+    kPositionRequest = 6,
+    kSetPositionRequest = 7,
+    kTruncateRequest = 8,
+    kLengthRequest = 9,
+    kLengthFromPathRequest = 10,
+    kLastModifiedRequest = 11,
+    kFlushRequest = 12,
+    kReadByteRequest = 13,
+    kWriteByteRequest = 14,
+    kReadRequest = 15,
+    kReadIntoRequest = 16,
+    kWriteFromRequest = 17,
+    kCreateLinkRequest = 18,
+    kDeleteLinkRequest = 19,
+    kLinkTargetRequest = 20,
+    kTypeRequest = 21,
+    kIdenticalRequest = 22,
+    kStatRequest = 23
   };
 
   enum FileStat {
     // These match the constants in FileStat in file_system_entity.dart.
     kType = 0,
     kCreatedTime = 1,
     kModifiedTime = 2,
     kAccessedTime = 3,
     kMode = 4,
     kSize = 5,
@@ skipping 52 matching lines @@
   static bool Create(const char* path);
   static bool CreateLink(const char* path, const char* target);
   static bool Delete(const char* path);
   static bool DeleteLink(const char* path);
   static off_t LengthFromPath(const char* path);
   static void Stat(const char* path, int64_t* data);
   static time_t LastModified(const char* path);
   static char* LinkTarget(const char* pathname);
   static bool IsAbsolutePath(const char* path);
   static char* GetCanonicalPath(const char* path);
-  static char* GetContainingDirectory(char* path);
   static const char* PathSeparator();
   static const char* StringEscapedPathSeparator();
   static Type GetType(const char* path, bool follow_links);
   static Identical AreIdentical(const char* file_1, const char* file_2);
   static StdioHandleType GetStdioHandleType(int fd);
 
   static FileOpenMode DartModeToFileMode(DartFileOpenMode mode);
 
   static Dart_Port GetServicePort();
 
  private:
   explicit File(FileHandle* handle) : handle_(handle) { }
   void Close();
 
   static const int kClosedFd = -1;
 
   // FileHandle is an OS specific class which stores data about the file.
   FileHandle* handle_;  // OS specific handle for the file.
 
   static NativeService file_service_;
 
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_FILE_H_