Replaced uses of std::chrono with GetTimeInSeconds

A monotonic clock (e.g. clock_gettime(2), GetTickCount64) would be more
appropriate.

Mesh/search.hpp

@@ -3,10 +3,11 @@
 #include <iterator>
 #include <functional>
 #include <algorithm>
-#include <chrono>
 
 #include <boost/functional.hpp>
 
+#include "OS.h"
+
 namespace search {
 
 template<typename T>
@@ -189,9 +190,9 @@ void large_neighborhood_search(State &state, Selector &selector,
   typedef typename selector_traits<Selector>::fragment_type fragment;
   typedef typename search_traits<Search>::assignment_type assignment;
 
-  using namespace std::chrono;
-  auto start = steady_clock::now();
-  while (steady_clock::now() - start < time_limit * 1s) {
+  /* TODO: Use a monotonic clock instead */
+  double start = GetTimeInSeconds();
+  while (GetTimeInSeconds() - start < time_limit) {
     fragment fragment(selector(state));
     assignment assignment(search(state, fragment));
     assignment(state, fragment);
@@ -349,14 +350,13 @@ void monte_carlo_tree_search(State &state, Successor &fn, Evaluator &eval) {
       actions[0](state).apply(state);
     }
     else {
-      using namespace std::chrono;
-
       mcts_node<score> node;
 
       size_t i;
 
-      auto start = steady_clock::now();
-      for (i = 0; (steady_clock::now() - start) < 1s; i++) {
+      /* TODO: Use a monotonic clock instead */
+      double start = GetTimeInSeconds();
+      for (i = 0; (GetTimeInSeconds() - start) < 1.0; i++) {
         mcts_simulation(&node, state, fn, eval, i,
                         actions.begin(), actions.end());
       }