[windows] Make most file_win.cc functions use malloc for string conversions.

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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 139 matching lines @@
   void DeleteWeakHandle(Dart_Isolate isolate) {
     Dart_DeleteWeakPersistentHandle(isolate, weak_handle_);
     weak_handle_ = NULL;
   }
 
   // Open the file with the given path. The file is always opened for
   // reading. If mode contains kWrite the file is opened for both
   // reading and writing. If mode contains kWrite and the file does
   // not exist the file is created. The file is truncated to length 0 if
   // mode contains kTruncate. Assumes we are in an API scope.
-  static File* ScopedOpen(const char* path, FileOpenMode mode);
-
-  // Like ScopedOpen(), but no API scope is needed.
   static File* Open(const char* path, FileOpenMode mode);
 
-  // Caution! On Windows, the static functions below may call
-  // Dart_ScopeAllocate() to do string conversions! If you call these functions
-  // without a scope, they will fail on Windows!
-
   // Create a file object for the specified stdio file descriptor
   // (stdin, stout or stderr).
   static File* OpenStdio(int fd);
 
   static bool Exists(const char* path);
   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 bool Rename(const char* old_path, const char* new_path);
   static bool RenameLink(const char* old_path, const char* new_path);
   static bool Copy(const char* old_path, const char* new_path);
   static int64_t LengthFromPath(const char* path);
   static void Stat(const char* path, int64_t* data);
   static time_t LastModified(const char* path);
-  static const char* LinkTarget(const char* pathname);
   static bool IsAbsolutePath(const char* path);
-  static const char* GetCanonicalPath(const 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);
 
+  // LinkTarget and GetCanonicalPath may call Dart_ScopeAllocate.
+  static const char* LinkTarget(const char* pathname);
+  static const char* GetCanonicalPath(const char* path);
+
   static FileOpenMode DartModeToFileMode(DartFileOpenMode mode);
 
   static CObject* ExistsRequest(const CObjectArray& request);
   static CObject* CreateRequest(const CObjectArray& request);
   static CObject* DeleteRequest(const CObjectArray& request);
   static CObject* RenameRequest(const CObjectArray& request);
   static CObject* CopyRequest(const CObjectArray& request);
   static CObject* OpenRequest(const CObjectArray& request);
   static CObject* ResolveSymbolicLinksRequest(const CObjectArray& request);
   static CObject* CloseRequest(const CObjectArray& request);
@@ skipping 39 matching lines @@
   Dart_WeakPersistentHandle weak_handle_;
 
   friend class ReferenceCounted<File>;
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_FILE_H_