remove unnecessary copy for send_tab_to_self_specifics.pb.h

I think we don't need this copy here introduced in
https://chromium-review.googlesource.com/c/chromium/src/+/1413214

Also this copy caused unnecessary build dependency serialization.

Bug: 937723
Change-Id: Ifa0e8466e83fbfe2278b880cb465b025fd22137e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1498800Reviewed-by: Jeffrey Cohen <jeffreycohen@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637890}

components/send_tab_to_self/proto/BUILD.gn

@@ -4,26 +4,10 @@
 
 import("//third_party/protobuf/proto_library.gni")
 
-copy("send_tab_to_self_header_include") {
-  sources = [
-    "send_tab_to_self_header_include.h",
-  ]
-  outputs = [
-    "$root_gen_dir" +
-        "/components/send_tab_to_self/proto/send_tab_to_self_specifics.pb.h",
-  ]
-  deps = [
-    "//components/sync/protocol:protocol",
-  ]
-}
-
 proto_library("send_tab_to_self_proto") {
   import_dirs = [ "//components/sync/protocol" ]
   sources = [
     "send_tab_to_self.proto",
   ]
-  deps = [
-    ":send_tab_to_self_header_include",
-    "//components/sync/protocol:protocol",
-  ]
+  link_deps = [ "//components/sync/protocol:protocol" ]
 }

components/send_tab_to_self/proto/send_tab_to_self_header_include.h

-// Copyright 2019 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.
-
-#ifndef COMPONENTS_SEND_TAB_TO_SELF_PROTO_SEND_TAB_TO_SELF_HEADER_INCLUDE_H_
-#define COMPONENTS_SEND_TAB_TO_SELF_PROTO_SEND_TAB_TO_SELF_HEADER_INCLUDE_H_
-
-// This is a bridge to include the generated proto header for the
-// send tab to self proto.
-#include "components/sync/protocol/send_tab_to_self_specifics.pb.h"
-
-#endif  // COMPONENTS_SEND_TAB_TO_SELF_PROTO_SEND_TAB_TO_SELF_HEADER_INCLUDE_H_