Base: Don't check for thread restrictions when closing a file doesn't do IO.

base/files/file_win.cc

 // Copyright (c) 2012 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 "base/files/file.h"
 
 #include <io.h>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 86 matching lines @@
 }
 
 bool File::IsValid() const {
   return file_.IsValid();
 }
 PlatformFile File::TakePlatformFile() {
   return file_.Take();
 }
 
 void File::Close() {
-  base::ThreadRestrictions::AssertIOAllowed();
-  file_.Close();
+  if (file_.IsValid()) {
+    base::ThreadRestrictions::AssertIOAllowed();
+    file_.Close();
+  }
 }
 
 int64 File::Seek(Whence whence, int64 offset) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
   if (offset < 0)
     return -1;
 
   LARGE_INTEGER distance, res;
   distance.QuadPart = offset;
@@ skipping 204 matching lines @@
                                   last_error);
       return FILE_ERROR_FAILED;
   }
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   file_.Set(file);
 }
 
 }  // namespace base