Record UMA statistics for file_stream operations.

net/base/net_errors_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/net_errors.h"
 
 #include <errno.h>
+#include <stdlib.h>
+#include <string>
+#include <unistd.h>
 
 #include "base/logging.h"
+#include "base/stringprintf.h"
 
 namespace net {
 
 Error MapSystemError(int os_error) {
+  if (os_error != 0)
+    DVLOG(2) << "Error " << os_error;
+
   // There are numerous posix error codes, but these are the ones we thus far
   // find interesting.
   switch (os_error) {
     case EAGAIN:
 #if EWOULDBLOCK != EAGAIN
     case EWOULDBLOCK:
 #endif
       return ERR_IO_PENDING;
     case EACCES:
       return ERR_ACCESS_DENIED;
@@ skipping 67 matching lines @@
     case ENOTSUP:  // Operation not supported.
       return ERR_NOT_IMPLEMENTED;
     case EPERM:  // Operation not permitted.
       return ERR_ACCESS_DENIED;
     case EROFS:  // Read-only file system.
       return ERR_ACCESS_DENIED;
     case ETXTBSY:  // Text file busy.
       return ERR_ACCESS_DENIED;
     case EUSERS:  // Too many users.
       return ERR_INSUFFICIENT_RESOURCES;
+    case EMFILE:  // Too many open files.
+      return ERR_INSUFFICIENT_RESOURCES;
 
     case 0:
       return OK;
     default:
       LOG(WARNING) << "Unknown error " << os_error
                    << " mapped to net::ERR_FAILED";
       return ERR_FAILED;
   }
 }
 
 }  // namespace net