Improve init bootcharting.

Most notably, there's no longer any need to guess an end time.

Bug: http://b/23478578
Bug: http://b/33450491
Test: rebooted with bootcharting on/off
Change-Id: Icb7d6859581da5526d77dfc5aa4d57c9bfbfd7e2
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 76e3d6e..fc0459c 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -1023,7 +1023,7 @@
 BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
     constexpr std::size_t kMax = std::numeric_limits<std::size_t>::max();
     static const Map builtin_functions = {
-        {"bootchart_init",          {0,     0,    do_bootchart_init}},
+        {"bootchart",               {1,     1,    do_bootchart}},
         {"chmod",                   {2,     2,    do_chmod}},
         {"chown",                   {2,     3,    do_chown}},
         {"class_reset",             {1,     1,    do_class_reset}},