Support dumping mainline relevant service pre-boot into bugreport

Append any information dumped in /data/misc/prereboot folder into
bugreport if found. Such folder should contain needed information
relatives to the last reboot only. In local test, it's ~= 900k before
compressed and ~= 100k after compressed in current design.

Bug: 145203410
Test: Manual triggered dumpstate, checked the data was appended properly.
Change-Id: I14156b56c86df9314782a069dc974e9f708a5b5a
diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index d705fa8..498f727 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -149,6 +149,7 @@
 #define RECOVERY_DATA_DIR "/data/misc/recovery"
 #define UPDATE_ENGINE_LOG_DIR "/data/misc/update_engine_log"
 #define LOGPERSIST_DATA_DIR "/data/misc/logd"
+#define PREREBOOT_DATA_DIR "/data/misc/prereboot"
 #define PROFILE_DATA_DIR_CUR "/data/misc/profiles/cur"
 #define PROFILE_DATA_DIR_REF "/data/misc/profiles/ref"
 #define XFRM_STAT_PROC_FILE "/proc/net/xfrm_stat"
@@ -1555,6 +1556,7 @@
         ds.AddDir(PROFILE_DATA_DIR_CUR, true);
         ds.AddDir(PROFILE_DATA_DIR_REF, true);
     }
+    ds.AddDir(PREREBOOT_DATA_DIR, false);
     add_mountinfo();
     DumpIpTablesAsRoot();
     DumpDynamicPartitionInfo();