[debugd] sandbox helpers explicitly

Sandbox helpers as debugd/debugd (like they are now) by default, so the only
change from this CL is that the debug daemon itself runs as root.

CQ-DEPEND=Icc5d7709eac3b11a8098369fa6666235da639f38
BUG=chromium-os:35122
TEST=platform_DebugDaemon

Change-Id: I0cc4b7ed3fd63068dcba4f1c72f2537ebbc1a151
Signed-off-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/37843
diff --git a/debugd/src/process_with_output.cc b/debugd/src/process_with_output.cc
index b9f8bc0..b15376e 100644
--- a/debugd/src/process_with_output.cc
+++ b/debugd/src/process_with_output.cc
@@ -20,6 +20,8 @@
 }
 
 bool ProcessWithOutput::Init() {
+  if (!SandboxedProcess::Init())
+    return false;
   outfile_ = file_util::CreateAndOpenTemporaryFile(&outfile_path_);
   if (!outfile_)
     return false;