metrics: use abs() for integer only.

This cast the type of the paramenter of abs() to integer before
calling the abs() function.

BUG=chromium:352331
TEST=FEATURES="test" emerge-amd64-generic platform2 passes.

Change-Id: Id8b994b743345456f14194b45f3a288b7e3b74f3
Reviewed-on: https://chromium-review.googlesource.com/189849
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Commit-Queue: Yunlian Jiang <yunlian@chromium.org>
diff --git a/metrics/metrics_library_test.cc b/metrics/metrics_library_test.cc
index 1658645..0a0768b 100644
--- a/metrics/metrics_library_test.cc
+++ b/metrics/metrics_library_test.cc
@@ -151,7 +151,7 @@
   ASSERT_EQ(!to_value, lib_.AreMetricsEnabled());
   EXPECT_CALL(*device_policy_, GetMetricsEnabled(_))
       .WillOnce(SetMetricsPolicy(to_value));
-  ASSERT_LT(abs(time(NULL) - lib_.cached_enabled_time_), 5);
+  ASSERT_LT(abs(static_cast<int>(time(NULL) - lib_.cached_enabled_time_)), 5);
   // Sleep one second (or cheat to be faster).
   --lib_.cached_enabled_time_;
   ASSERT_EQ(to_value, lib_.AreMetricsEnabled());