Revert 22380 to investigate windows build break.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 22381)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -745,12 +745,10 @@
     Dart_IsolateUnhandledExceptionCallback unhandled,
     Dart_IsolateShutdownCallback shutdown,
     Dart_FileOpenCallback file_open,
-    Dart_FileReadCallback file_read,
     Dart_FileWriteCallback file_write,
     Dart_FileCloseCallback file_close) {
   const char* err_msg = Dart::InitOnce(create, interrupt, unhandled, shutdown,
-                                       file_open, file_read, file_write,
-                                       file_close);
+                                       file_open, file_write, file_close);
   if (err_msg != NULL) {
     OS::PrintErr("Dart_Initialize: %s\n", err_msg);
     return false;