shill: Fix most of warnings from cpplint

Fix most cpplinter's warnings. On a few occasisions, the warnings
produced were false-positives, so added explicit // NOLINT comment
overrides.

There were a few instances of disallowed non-const reference usage
(reported as runtime/reference error by cpplint) for
"DBus::Error &error" which should potentially be changed
to pointers to comply with C++ coding style but I will let Shill
owners do that since there is quite a few of those and the
change isn't brain-dead simple...

BUG=None
TEST=platform2 still compiles and all unit tests pass.

Change-Id: Ic2e31896aa13d20eeb1a85dee74f3db8cccfde2e
Reviewed-on: https://chromium-review.googlesource.com/204164
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/mm1_modem_proxy.h b/mm1_modem_proxy.h
index be9c458..09c9830 100644
--- a/mm1_modem_proxy.h
+++ b/mm1_modem_proxy.h
@@ -6,6 +6,7 @@
 #define SHILL_MM1_MODEM_PROXY_H_
 
 #include <string>
+#include <vector>
 
 #include "dbus_proxies/org.freedesktop.ModemManager1.Modem.h"
 #include "shill/dbus_properties.h"
@@ -118,8 +119,9 @@
   template<typename TraceMsgT, typename CallT, typename CallbackT,
       typename... ArgTypes>
       void BeginCall(
-          const TraceMsgT &trace_msg, const CallT &call, CallbackT &callback,
-          Error *error, int timeout, ArgTypes... rest);
+          const TraceMsgT &trace_msg, const CallT &call,
+          const CallbackT &callback, Error *error, int timeout,
+          ArgTypes... rest);
 
   DISALLOW_COPY_AND_ASSIGN(ModemProxy);
 };