Add a flag to dump IPC messages sent from the renderer to the browser.

tools/ipc_fuzzer/dump/message_dump.cc

Index: tools/ipc_fuzzer/dump/message_dump.cc
diff --git a/tools/ipc_fuzzer/dump/message_dump.cc b/tools/ipc_fuzzer/dump/message_dump.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fafa86cfadafbb25a6de0d28bd2b172344e29012
--- /dev/null
+++ b/tools/ipc_fuzzer/dump/message_dump.cc
@@ -0,0 +1,62 @@
+// Copyright (c) 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.
+
+#include "base/files/file_path.h"
+#include "base/process/process.h"
+#include "base/strings/string_number_conversions.h"
+#include "ipc/ipc_channel_proxy.h"
+#include "tools/ipc_fuzzer/message_lib/message_file.h"
+
+#if defined(OS_WIN)
+#define IntToStringType base::IntToString16
+#else
+#define IntToStringType base::IntToString
+#endif
+
+namespace ipc_fuzzer {
+
+class IPCDump : public IPC::ChannelProxy::OutgoingMessageFilter {
+ public:
+  ~IPCDump() {
+    base::FilePath::StringType pid_string =
+        IntToStringType(base::Process::Current().Pid());

[inferno, 2015/03/05 22:11:59]

base::Process::Current().Pid() is base::ProcessId. On windows, this is an dword
(unsigned int), so you need to use base::UIntToString16. Please also put a
comment in the #define above.

maybe s/IntToStringType/PidToStringType

+    base::FilePath output_file_path =
+        dump_directory().Append(pid_string + FILE_PATH_LITERAL(".ipcdump"));
+
+    MessageFile::Write(output_file_path, messages_);
+  }
+
+  IPC::Message* Rewrite(IPC::Message* message) override {
+    messages_.push_back(new IPC::Message(*message));
+    return message;
+  }
+
+  base::FilePath dump_directory() const { return dump_directory_; }
+
+  void set_dump_directory(const base::FilePath& dump_directory) {
+    dump_directory_ = dump_directory;
+  }
+
+ private:
+  MessageVector messages_;
+  base::FilePath dump_directory_;
+};
+
+IPCDump g_ipcdump;
+
+}  // namespace ipc_fuzzer
+
+// Entry point avoiding mangled names.
+extern "C" {
+IPC_EXPORT IPC::ChannelProxy::OutgoingMessageFilter* GetFilter(void);
+IPC_EXPORT void SetDumpDirectory(const base::FilePath& dump_directory);
+}
+
+IPC::ChannelProxy::OutgoingMessageFilter* GetFilter(void) {
+  return &ipc_fuzzer::g_ipcdump;
+}
+
+void SetDumpDirectory(const base::FilePath& dump_directory) {
+  ipc_fuzzer::g_ipcdump.set_dump_directory(dump_directory);
+}