Move shared files in net/quic/ into net/quic/core/

net/quic/core/proto/source_address_token.proto

 // Copyright 2015 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.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 import "cached_network_parameters.proto";
 
@@ skipping 12 matching lines @@
   // initial parameter selection in future connections.
   optional CachedNetworkParameters cached_network_parameters = 3;
 };
 
 // SourceAddressTokens are simply lists of SourceAddressToken messages.
 message SourceAddressTokens {
   // This field has id 4 to avoid ambiguity between the serialized form of
   // SourceAddressToken vs SourceAddressTokens.
   repeated SourceAddressToken tokens = 4;
 };