This adds some plumbing for propagating the status and error code of a

chrome/common/notification_type.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_COMMON_NOTIFICATION_TYPE_H_
 #define CHROME_COMMON_NOTIFICATION_TYPE_H_
 #pragma once
 
 // This file describes various types used to describe and filter notifications
 // that pass through the NotificationService.
@@ skipping 515 matching lines @@
     // ephemeral task; register for AllSources() to receive this notification.
     // The details are in a Details<ChildProcessInfo>.
     CHILD_PROCESS_HOST_CONNECTED,
 
     // This message is sent after a ChildProcessHost is disconnected from the
     // child process.  There is no usable source, since it is sent from an
     // ephemeral task; register for AllSources() to receive this notification.
     // The details are in a Details<ChildProcessInfo>.
     CHILD_PROCESS_HOST_DISCONNECTED,
 
-    // This message is sent when a child process disappears unexpectedly.
-    // There is no usable source, since it is sent from an ephemeral task;
-    // register for AllSources() to receive this notification.  The details are
-    // in a Details<ChildProcessInfo>.
+    // This message is sent when a child process disappears
+    // unexpectedly as a result of a crash.  There is no usable
+    // source, since it is sent from an ephemeral task; register for
+    // AllSources() to receive this notification.  The details are in
+    // a Details<ChildProcessInfo>.
     CHILD_PROCESS_CRASHED,
 
+    // This message is sent when a child process disappears
+    // unexpectedly as a result of a termination signal.  There is no
+    // usable source, since it is sent from an ephemeral task;
+    // register for AllSources() to receive this notification.  The
+    // details are in a Details<ChildProcessInfo>.
+    CHILD_PROCESS_WAS_KILLED,
+
     // This message indicates that an instance of a particular child was
     // created in a page.  (If one page contains several regions rendered by
     // the same child, this notification will occur once for each region
     // during the page load.)
     //
     // There is no usable source, since it is sent from an ephemeral task;
     // register for AllSources() to receive this notification.  The details are
     // in a Details<ChildProcessInfo>.
     CHILD_INSTANCE_CREATED,
 
@@ skipping 653 matching lines @@
 };
 
 inline bool operator==(NotificationType::Type a, NotificationType b) {
   return a == b.value;
 }
 inline bool operator!=(NotificationType::Type a, NotificationType b) {
   return a != b.value;
 }
 
 #endif  // CHROME_COMMON_NOTIFICATION_TYPE_H_