Add support for sending protobuf messages over IPC.

chrome/common/safe_browsing/ipc_protobuf_message_test.proto

Index: chrome/common/safe_browsing/ipc_protobuf_message_test.proto
diff --git a/chrome/common/safe_browsing/ipc_protobuf_message_test.proto b/chrome/common/safe_browsing/ipc_protobuf_message_test.proto
new file mode 100644
index 0000000000000000000000000000000000000000..8148461a68b9fc80b997314c1b80dd5c3b53e782
--- /dev/null
+++ b/chrome/common/safe_browsing/ipc_protobuf_message_test.proto
@@ -0,0 +1,19 @@
+// 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;
+
+message SubMessage {
+  optional int32 foo = 1;
+}
+
+message TestMessage {
+  optional int32 fund_int = 1;
+  optional string op_comp_string = 2;
+  optional bytes op_comp_bytes = 3;
+  optional SubMessage op_comp_sub = 4;
+  repeated SubMessage rep_comp_sub = 5;
+}