Revert of Start all children in their own PID namespace.

content/zygote/zygote_main_linux.cc

Index: content/zygote/zygote_main_linux.cc
diff --git a/content/zygote/zygote_main_linux.cc b/content/zygote/zygote_main_linux.cc
index b9dfdcabfb6f730fcd280318c6b502572a8a6e29..96fac2194377a0f6c43b9ba22c4ff0b8b74b5480 100644
--- a/content/zygote/zygote_main_linux.cc
+++ b/content/zygote/zygote_main_linux.cc
@@ -40,7 +40,6 @@
 #include "content/public/common/zygote_fork_delegate_linux.h"
 #include "content/zygote/zygote_linux.h"
 #include "crypto/nss_util.h"
-#include "sandbox/linux/services/credentials.h"
 #include "sandbox/linux/services/init_process_reaper.h"
 #include "sandbox/linux/services/libc_urandom_override.h"
 #include "sandbox/linux/services/namespace_sandbox.h"
@@ -79,11 +78,6 @@
   for (const auto& it : fds) {
     PCHECK(0 == IGNORE_EINTR(close(it)));
   }
-}
-
-void RunTwoClosures(const base::Closure* first, const base::Closure* second) {
-  first->Run();
-  second->Run();
 }
 
 }  // namespace
@@ -413,20 +407,12 @@
   return true;
 }
 
-static void DropAllCapabilities(int proc_fd) {
-  CHECK(sandbox::Credentials::DropAllCapabilities(proc_fd));
-}
-
 static void EnterNamespaceSandbox(LinuxSandbox* linux_sandbox,
                                   base::Closure* post_fork_parent_callback) {
   linux_sandbox->EngageNamespaceSandbox();
 
   if (getpid() == 1) {
-    base::Closure drop_all_caps_callback =
-        base::Bind(&DropAllCapabilities, linux_sandbox->proc_fd());
-    base::Closure callback = base::Bind(
-        &RunTwoClosures, &drop_all_caps_callback, post_fork_parent_callback);
-    CHECK(CreateInitProcessReaper(&callback));
+    CHECK(CreateInitProcessReaper(post_fork_parent_callback));
   }
 }