Ignore kill termination status when shutting down a child process.

content/browser/browser_child_process_host_impl.cc

Index: content/browser/browser_child_process_host_impl.cc
diff --git a/content/browser/browser_child_process_host_impl.cc b/content/browser/browser_child_process_host_impl.cc
index 23f4c05c188a419299b921f272fb2a03e42042ab..a57e1fd6a564dfe05422f2c6c1e26490f3aa9a1f 100644
--- a/content/browser/browser_child_process_host_impl.cc
+++ b/content/browser/browser_child_process_host_impl.cc
@@ -395,6 +395,17 @@ void BrowserChildProcessHostImpl::OnChildDisconnected() {
       case base::TERMINATION_STATUS_PROCESS_WAS_KILLED_BY_OOM:
 #endif
       case base::TERMINATION_STATUS_PROCESS_WAS_KILLED: {
+        // If the IPC channel was disconnected after a shutdown request, we
+        // expect the process to be dead. However, if the IPC channel uses
+        // ChannelMojo, it is not true that the process is dead when the
+        // disconnection event comes in. This is because Mojo does an orderly
+        // shutdown in the child process and so the child may not be dead by the
+        // time we get here. If the child isn't dead, the call to
+        // GetTerminationStatus() above may cause the child to be killed because
+        // GetTerminationStatus(known_dead=true) SIGKILLs the process before
+        // waiting for it.
+        if (child_process_host_->IsShuttingDown())
+          break;
         delegate_->OnProcessCrashed(exit_code);
         BrowserThread::PostTask(
             BrowserThread::UI, FROM_HERE,
@@ -417,7 +428,8 @@ void BrowserChildProcessHostImpl::OnChildDisconnected() {
                               data_.process_type,
                               PROCESS_TYPE_MAX);
 #if defined(OS_CHROMEOS)
-    if (status == base::TERMINATION_STATUS_PROCESS_WAS_KILLED_BY_OOM) {
+    if (status == base::TERMINATION_STATUS_PROCESS_WAS_KILLED_BY_OOM &&
+        !child_process_host_->IsShuttingDown()) {
       UMA_HISTOGRAM_ENUMERATION("ChildProcess.Killed2.OOM",
                                 data_.process_type,
                                 PROCESS_TYPE_MAX);