Fixes some memory leaks in //runtime/bin

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>
 #include <sys/types.h>
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 
-
 namespace dart {
 namespace bin {
 
 // Forward declaration.
 class FileHandle;
 
 class File {
  public:
   enum FileOpenMode {
     kRead = 0,
@@ skipping 95 matching lines @@
   // Lock range of a file.
   bool Lock(LockType lock, int64_t start, int64_t end);
 
   // Returns whether the file has been closed.
   bool IsClosed();
 
   // 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.
+  // 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);
 
   // 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 char* LinkTarget(const char* pathname);
+  static const char* LinkTarget(const char* pathname);
   static bool IsAbsolutePath(const char* path);
-  static char* GetCanonicalPath(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);
 
   static FileOpenMode DartModeToFileMode(DartFileOpenMode mode);
 
   static CObject* ExistsRequest(const CObjectArray& request);
   static CObject* CreateRequest(const CObjectArray& request);
@@ skipping 21 matching lines @@
   static CObject* LinkTargetRequest(const CObjectArray& request);
   static CObject* TypeRequest(const CObjectArray& request);
   static CObject* IdenticalRequest(const CObjectArray& request);
   static CObject* StatRequest(const CObjectArray& request);
   static CObject* LockRequest(const CObjectArray& request);
 
  private:
   explicit File(FileHandle* handle) : handle_(handle) { }
   void Close();
 
+  static File* FileOpenW(const wchar_t* system_name, FileOpenMode mode);
+
   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.
 
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_FILE_H_