Remove object_utils.h.

Break into object_lock, field_helper and method_helper.
Clean up header files following this.
Also tidy some of the Handle code in response to compiler errors when resolving
the changes in this CL.

Change-Id: I73e63015a0f02a754d0866bfaf58208aebcaa295
diff --git a/sigchainlib/sigchain.h b/sigchainlib/sigchain.h
index f6f2253..a4ce81c 100644
--- a/sigchainlib/sigchain.h
+++ b/sigchainlib/sigchain.h
@@ -18,10 +18,13 @@
 #define ART_SIGCHAINLIB_SIGCHAIN_H_
 
 #include <signal.h>
+
 namespace art {
 
 void ClaimSignalChain(int signal, struct sigaction* oldaction);
+
 void UnclaimSignalChain(int signal);
+
 void InvokeUserSignalHandler(int sig, siginfo_t* info, void* context);
 
 }   // namespace art