Read RSS high watermark

The value is read from /proc/PID/status or memory.max_usage_in_bytes (for devices with per-app memcg enabled).

Reading the value takes about 2ms per process.
Full snapshot taken by statsd is around 300ms.

Results: https://docs.google.com/spreadsheets/d/1vG9ku8Uu8104CmKbO4cNeEKVeeByvHY--p0_dK1GAdA/edit?usp=sharing

Bug: 115477992
Test: atest FrameworksServicesTests
Change-Id: I87995cbd85085375ade685f29e986ba173f9693e
diff --git a/cmds/statsd/src/external/StatsPullerManager.cpp b/cmds/statsd/src/external/StatsPullerManager.cpp
index 5a0172b..66392f8 100644
--- a/cmds/statsd/src/external/StatsPullerManager.cpp
+++ b/cmds/statsd/src/external/StatsPullerManager.cpp
@@ -169,7 +169,7 @@
           new ResourceHealthManagerPuller(android::util::BATTERY_VOLTAGE)}},
         // process_memory_state
         {android::util::PROCESS_MEMORY_STATE,
-         {{4, 5, 6, 7, 8},
+         {{4, 5, 6, 7, 8, 9},
           {2, 3},
           1 * NS_PER_SEC,
           new StatsCompanionServicePuller(android::util::PROCESS_MEMORY_STATE)}},