Add simple trace logging of received IPC messages

chrome/common/all_messages.h

Index: chrome/common/all_messages.h
diff --git a/chrome/common/all_messages.h b/chrome/common/all_messages.h
index 7eec49d9808f0b9d5f29114db5caba727d948e4e..5b396b6bed257896cd506b05eb5ffe24807b2e6b 100644
--- a/chrome/common/all_messages.h
+++ b/chrome/common/all_messages.h
@@ -3,9 +3,11 @@
 // found in the LICENSE file.
 
 // Multiply-included file, hence no include guard.
-// Inclusion of all message files present in the system.  Keep this file
+// Inclusion of all message files present in chrome.  Keep this file
 // up-to-date when adding a new value to enum IPCMessageStart in
 // ipc/ipc_message_utils.h to include the corresponding message file.
+// Messages classes used exclusively outside of chrome should instead get an
+// exemption in chrome/tools/ipclist/ipclist.cc.
 #include "chrome/browser/importer/profile_import_process_messages.h"
 // We can't make common_message_generator.h include automation_messages, since
 // otherwise the Chrome Frame binaries will link in a lot of unrelated chrome