chrome: respect --child-clean-exit.

content/zygote/zygote_linux.cc

Index: content/zygote/zygote_linux.cc
diff --git a/content/zygote/zygote_linux.cc b/content/zygote/zygote_linux.cc
index 893002281218e863a33bfeca97cab5f949d23efe..9dfd56c746c237617f01ff91e2bc24eed4d0c9d7 100644
--- a/content/zygote/zygote_linux.cc
+++ b/content/zygote/zygote_linux.cc
@@ -5,6 +5,7 @@
 #include "content/zygote/zygote_linux.h"
 
 #include <fcntl.h>
+#include <pthread.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>
@@ -24,6 +25,7 @@
 #include "content/common/set_process_title.h"
 #include "content/common/zygote_commands_linux.h"
 #include "content/public/common/content_descriptors.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/sandbox_linux.h"
 #include "content/public/common/zygote_fork_delegate_linux.h"
@@ -110,7 +112,18 @@ bool Zygote::HandleRequestFromBrowser(int fd) {
 
   if (len == 0 || (len == -1 && errno == ECONNRESET)) {
     // EOF from the browser. We should die.
-    _exit(0);
+    if (CommandLine::ForCurrentProcess()->
+        HasSwitch(switches::kChildCleanExit)) {
+      // Zygote children are reaped in a separate detached thread (see the
+      // implementation of EnsureProcessGetsReaped()). If we _exit() or exit()
+      // here, the reaping wait may not have completed. For this reason, we
+      // only terminate this thread (instead of terminating the whole process).
+      // The zygote will then exit only when all children have exited and have
+      // been reaped.
+      pthread_exit(0);
+    }
+    else
+      _exit(0);
     return false;
   }
 
@@ -196,7 +209,9 @@ void Zygote::HandleGetTerminationStatus(int fd,
   if (UsingSUIDSandbox())
     child = real_pids_to_sandbox_pids[child];
   if (child) {
-    if (known_dead) {
+    if (known_dead &&
+        !CommandLine::ForCurrentProcess()->
+        HasSwitch(switches::kChildCleanExit)) {
       // If we know that the process is already dead and the kernel is cleaning
       // it up, we do want to wait until it becomes a zombie and not risk
       // returning eroneously that it is still running. However, we do not