debugd: Fix coding style and cpplint issues.

BUG=chromium:385849
TEST=`FEATURES=test emerge-$BOARD platform2`
TEST=`cpplint.py --root=src --filter=-build/include src/{*.h,*.cc,*/*.cc}`

Change-Id: Ia2475d6ee287dc727c3b2ffe139e9cc8bfe2e2e5
Reviewed-on: https://chromium-review.googlesource.com/204391
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/debugd/src/sandboxed_process.h b/debugd/src/sandboxed_process.h
index f335be0..e999a98 100644
--- a/debugd/src/sandboxed_process.h
+++ b/debugd/src/sandboxed_process.h
@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef SANDBOXED_PROCESS_H
-#define SANDBOXED_PROCESS_H
+#ifndef SANDBOXED_PROCESS_H_
+#define SANDBOXED_PROCESS_H_
+
+#include <string>
 
 #include <chromeos/process.h>
 
@@ -37,6 +39,6 @@
   std::string group_;
 };
 
-};  // namespace debugd
+}  // namespace debugd
 
-#endif  // SANDBOXED_PROCESS_H
+#endif  // SANDBOXED_PROCESS_H_