Don't use global variables for capturing stdio.

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 169 matching lines @@
   static CObject* WriteFromRequest(const CObjectArray& request);
   static CObject* CreateLinkRequest(const CObjectArray& request);
   static CObject* DeleteLinkRequest(const CObjectArray& request);
   static CObject* RenameLinkRequest(const CObjectArray& request);
   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);
 
+  static void set_capture_stdout(bool value) {
+    capture_stdout_ = value;
+    capture_any_ = (capture_stdout_ || capture_stderr_);
+  }
+  static bool capture_stdout() { return capture_stdout_; }
+
+  static void set_capture_stderr(bool value) {
+    capture_stderr_ = value;
+    capture_any_ = (capture_stdout_ || capture_stderr_);
+  }
+  static bool capture_stderr() { return capture_stderr_; }
+
  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 bool capture_stdout_;
+  static bool capture_stderr_;
+  static bool capture_any_;
+
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_FILE_H_