Better handling of trim/benchmark results.

Request benchmarking of devices once per week during normal fstrim
maintenance window.  Tunable parameter gives us the ability to change
frequency through global setting.

Track individual benchmark and trim results for each volume, and
use scrubbed volume identifier (based on adoptiong age) when logging
stats to drop box.  Track last benchmark and trim time for each
volume separately.

Bug: 21831325
Change-Id: I53b3ed788f7820c2e5bceb2840339f5b4aada3f0
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index e5afdde..4e13758 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -6324,6 +6324,9 @@
        /** Timeout in milliseconds to wait for NTP server. {@hide} */
        public static final String NTP_TIMEOUT = "ntp_timeout";
 
+       /** {@hide} */
+       public static final String STORAGE_BENCHMARK_INTERVAL = "storage_benchmark_interval";
+
        /**
         * Whether the package manager should send package verification broadcasts for verifiers to
         * review apps prior to installation.