Show actualy FD for files in Observatory.

runtime/bin/file.cc

 // 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.
 
 #include "bin/file.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/io_buffer.h"
 #include "bin/thread.h"
@@ skipping 93 matching lines @@
 
 
 void FUNCTION_NAME(File_Close)(Dart_NativeArguments args) {
   File* file = GetFilePointer(Dart_GetNativeArgument(args, 0));
   ASSERT(file != NULL);
   delete file;
   Dart_SetReturnValue(args, Dart_NewInteger(0));
 }
 
 
+void FUNCTION_NAME(File_GetFD)(Dart_NativeArguments args) {
+  File* file = GetFilePointer(Dart_GetNativeArgument(args, 0));
+  ASSERT(file != NULL);
+  Dart_SetReturnValue(args, Dart_NewInteger(file->GetFD()));
+}
+
+
 void FUNCTION_NAME(File_ReadByte)(Dart_NativeArguments args) {
   File* file = GetFilePointer(Dart_GetNativeArgument(args, 0));
   ASSERT(file != NULL);
   uint8_t buffer;
   int64_t bytes_read = file->Read(reinterpret_cast<void*>(&buffer), 1);
   if (bytes_read == 1) {
     Dart_SetReturnValue(args, Dart_NewInteger(buffer));
   } else if (bytes_read == 0) {
     Dart_SetReturnValue(args, Dart_NewInteger(-1));
   } else {
@@ skipping 1061 matching lines @@
     CObjectArray* wrapper = new CObjectArray(CObject::NewArray(2));
     wrapper->SetAt(0, new CObjectInt32(CObject::NewInt32(CObject::kSuccess)));
     wrapper->SetAt(1, result);
     return wrapper;
   }
   return CObject::IllegalArgumentError();
 }
 
 }  // namespace bin
 }  // namespace dart