Reland of land debugging for ipc related crash.

ipc/ipc_channel_common.cc

Index: ipc/ipc_channel_common.cc
diff --git a/ipc/ipc_channel_common.cc b/ipc/ipc_channel_common.cc
index 5438c661a301d5f7e467c646618242e5a53aef7b..1a227ad7c5ac052d116e145d6457040792b39ecc 100644
--- a/ipc/ipc_channel_common.cc
+++ b/ipc/ipc_channel_common.cc
@@ -5,6 +5,8 @@
 #include "ipc/ipc_channel.h"
 
 namespace IPC {
+
+static Channel::MessageVerifier g_message_verifier = nullptr;
 
 // static
 scoped_ptr<Channel> Channel::CreateClient(
@@ -56,6 +58,16 @@
 Channel::~Channel() {
 }
 
+// static
+void Channel::SetMessageVerifier(MessageVerifier verifier) {
+  g_message_verifier = verifier;
+}
+
+// static
+Channel::MessageVerifier Channel::GetMessageVerifier() {
+  return g_message_verifier;
+}
+
 bool Channel::IsSendThreadSafe() const {
   return false;
 }