Remove unused code from WebMimeRegistry.

content/child/simple_webmimeregistry_impl.cc

 // Copyright 2014 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 "content/child/simple_webmimeregistry_impl.h"
 
 #include "base/files/file_path.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 81 matching lines @@
 }
 
 WebString SimpleWebMimeRegistryImpl::wellKnownMimeTypeForExtension(
     const WebString& file_extension) {
   std::string mime_type;
   net::GetWellKnownMimeTypeFromExtension(
       base::FilePath::FromUTF16Unsafe(file_extension).value(), &mime_type);
   return WebString::fromUTF8(mime_type);
 }
 
-WebString SimpleWebMimeRegistryImpl::mimeTypeFromFile(
-    const WebString& file_path) {
-  std::string mime_type;
-  net::GetMimeTypeFromFile(base::FilePath::FromUTF16Unsafe(file_path),
-                           &mime_type);
-  return WebString::fromUTF8(mime_type);
-}
-
 }  // namespace content