Add support for sending protobuf messages over IPC.

chrome/common/safe_browsing/ipc_protobuf_message_macros.h

+// 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.
+
+// Protobuf Messages over IPC
+//
+// Protobuf messages are registered with IPC_PROTOBUF_MESSAGE_TRAITS_BEGIN() and
+// friends in much the same way as other externally-defined structs (see
+// ipc/ipc_message_macros.h). These macros also cause only registration of the
+// protobuf message type IPC with message generation. Within matching calls to
+// _BEGIN() and _END(), one may use:
+// - IPC_PROTOBUF_MESSAGE_TRAITS_OPTIONAL_FUNDAMENTAL_MEMBER() to register an
+//   optional field of fundamental type (any scalar message field type save
+//   "string" and "bytes").
+// - IPC_PROTOBUF_MESSAGE_TRAITS_OPTIONAL_COMPLEX_MEMBER() to register an
+//   optional field of complex type (scalar message field type "string" or
+//   "bytes", or another message type).
+// - IPC_PROTOBUF_MESSAGE_TRAITS_REPEATED_COMPLEX_MEMBER() to register a
+//   repeated field of complex type (scalar message field type "string" or
+//   "bytes", or another message type).
+//
+// Enum types in protobuf messages are registered with
+// IPC_ENUM_TRAITS_VALIDATE() as with any other enum. In this case, the
+// validation expression should be the _IsValid() function provided by the
+// generated protobuf code. For example:
+//
+//     IPC_ENUM_TRAITS_VALIDATE(MyEnumType, MyEnumType_IsValid(value))
+
+#ifndef CHROME_COMMON_SAFE_BROWSING_IPC_PROTOBUF_MESSAGE_MACROS_H_
+#define CHROME_COMMON_SAFE_BROWSING_IPC_PROTOBUF_MESSAGE_MACROS_H_
+
+#include <string>
+
+#define IPC_PROTOBUF_MESSAGE_TRAITS_BEGIN(message_name)                      \
+  namespace IPC {                                                            \
+  template <>                                                                \
+  struct IPC_MESSAGE_EXPORT ParamTraits<message_name> {                      \
+    typedef message_name param_type;                                         \
+    static void Write(Message* m, const param_type& p);                      \
+    static bool Read(const Message* m, PickleIterator* iter, param_type* p); \
+    static void Log(const param_type& p, std::string* l);                    \
+                                                                             \
+   private:                                                                  \
+    template <class P>                                                       \
+    static bool ReadParamF(const Message* m,                                 \
+                           PickleIterator* iter,                             \
+                           param_type* p,                                    \
+                           void (param_type::*setter_function)(P));          \
+  };                                                                         \
+  }  // namespace IPC
+
+#define IPC_PROTOBUF_MESSAGE_TRAITS_OPTIONAL_FUNDAMENTAL_MEMBER(name)
+#define IPC_PROTOBUF_MESSAGE_TRAITS_OPTIONAL_COMPLEX_MEMBER(name)
+#define IPC_PROTOBUF_MESSAGE_TRAITS_REPEATED_COMPLEX_MEMBER(name)
+#define IPC_PROTOBUF_MESSAGE_TRAITS_END()
+
+#endif  // CHROME_COMMON_SAFE_BROWSING_IPC_PROTOBUF_MESSAGE_MACROS_H_