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

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index f7a40cbb8cefedb334b2c08be6c4c81d8ebc5904..756f342a72ca25bdd190e41ed87d18ec18eeda66 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -127,6 +127,10 @@
 #include "extensions/renderer/script_context.h"
 #endif
 
+#if defined(ENABLE_IPC_FUZZER)
+#include "chrome/common/external_ipc_dumper.h"
+#endif
+
 #if defined(ENABLE_PRINTING)
 #include "chrome/renderer/printing/chrome_print_web_view_helper_delegate.h"
 #include "components/printing/renderer/print_web_view_helper.h"
@@ -466,6 +470,16 @@ void ChromeContentRendererClient::RenderThreadStarted() {
   WebSecurityPolicy::registerURLSchemeAsLocal(external_file_scheme);
 #endif
 
+#if defined(ENABLE_IPC_FUZZER)
+  if (command_line->HasSwitch(switches::kIpcDumpDirectory)) {
+    base::FilePath dump_directory =
+        command_line->GetSwitchValuePath(switches::kIpcDumpDirectory);
+    IPC::ChannelProxy::OutgoingMessageFilter* filter =
+        LoadExternalIPCDumper(dump_directory);
+    thread->GetChannel()->set_outgoing_message_filter(filter);
+  }
+#endif
+
   // chrome: and chrome-search: pages should not be accessible by bookmarklets
   // or javascript: URLs typed in the omnibox.
   WebSecurityPolicy::registerURLSchemeAsNotAllowingJavascriptURLs(