Remove net::Filter direct dependency on IsSupportedMimeType

net/base/network_delegate_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 "net/base/network_delegate_impl.h"
 
 #include "net/base/net_errors.h"
 
 namespace net {
 
@@ skipping 94 matching lines @@
   return false;
 }
 
 bool NetworkDelegateImpl::OnCancelURLRequestWithPolicyViolatingReferrerHeader(
     const URLRequest& request,
     const GURL& target_url,
     const GURL& referrer_url) const {
   return false;
 }
 
+bool NetworkDelegateImpl::OnIsSupportedMimeType(
+    const std::string& mime_type) const {
+  // ShellNetworkDelegate and ChromeNetworkDelegate provide actual
+  // implementations.
+  return false;
+}
+
 }  // namespace net