Update to build against libchrome-242728.

This CL updates metrics to build against libchrome-242728 and also converts
libmetrics into slotted libraries (libmetrics-180609 and libmetrics-242728).

BUG=chromium:341521
BUG=chromium:342866
CQ-DEPEND=CL:186027
CQ-DEPEND=CL:186026
CQ-DEPEND=CL:186037
CQ-DEPEND=CL:186092
CQ-DEPEND=CL:186028
CQ-DEPEND=CL:186029
CQ-DEPEND=CL:186038
CQ-DEPEND=CL:186093
CQ-DEPEND=CL:186100
CQ-DEPEND=CL:186039
TEST=Trybot run on paladin, release, and chromiumos-sdk builders.

Change-Id: I09dc3d47cfe24a22864abf217658c63493b35cba
Reviewed-on: https://chromium-review.googlesource.com/185187
Reviewed-by: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/metrics/timer.h b/metrics/timer.h
index b949773..ce88873 100644
--- a/metrics/timer.h
+++ b/metrics/timer.h
@@ -10,7 +10,11 @@
 #include <string>
 
 #include <base/memory/scoped_ptr.h>
+#if BASE_VER >= 242728
+#include <base/time/time.h>
+#else
 #include <base/time.h>
+#endif
 #include <gtest/gtest_prod.h>  // for FRIEND_TEST
 
 class MetricsLibraryInterface;