logd: statistics per-pid filter

Primarily gives access to the Chattiest TIDs and TAGs
associated with a pid.

Has a secondary effect of allowing us to pull out the
command line, comm and in some cases the associated
PACKAGE for a specific pid while the logs are still
present even if the executable is gone.

Bug: 26029733
Bug: 21615139
Change-Id: I1ea63165a680a9318360579b70b1512078ed5682
diff --git a/logd/LogBuffer.h b/logd/LogBuffer.h
index c1fec73..c1614e8 100644
--- a/logd/LogBuffer.h
+++ b/logd/LogBuffer.h
@@ -86,7 +86,7 @@
     int setSize(log_id_t id, unsigned long size);
     unsigned long getSizeUsed(log_id_t id);
     // *strp uses malloc, use free to release.
-    std::string formatStatistics(uid_t uid, unsigned int logMask);
+    std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
 
     void enableStatistics() {
         stats.enableStatistics();