chrome: respect --child-clean-exit.

content/app/content_main_runner.cc

Index: content/app/content_main_runner.cc
diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index 5bbdb9b35d81c001374fa3b495ae5430bc16224a..1e80ac034d8eefa3252321daf4be9ae318f0f8f8 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -5,6 +5,12 @@
 #include "content/public/app/content_main_runner.h"
 
 #include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#if defined(OS_POSIX)
+#include <errno.h>
+#endif  // OS_POSIX
+
 
 #include "base/allocator/allocator_extension.h"
 #include "base/at_exit.h"
@@ -786,6 +792,18 @@ class ContentMainRunnerImpl : public ContentMainRunner {
 
     exit_manager_.reset(NULL);
 
+#if defined(OS_POSIX)
+    // Wait for children to exit if --wait-for-children-before-exiting is
+    // passed.
+    if (CommandLine::ForCurrentProcess()->
+        HasSwitch(switches::kWaitForChildrenBeforeExiting)) {
+      for (;;) {
+        if (wait(NULL) < 0 && errno == ECHILD)
+          break;
+      }
+    }
+#endif  // OS_POSIX
+
     delegate_ = NULL;
     is_shutdown_ = true;
   }