Add Memory category to atrace.

We've added a couple of new tracepoints for memory, and this change adds
them to atrace via a 'memory' category to make them easy to access.

Bug: 117892691
Test: manual

Change-Id: I6ae20b5c0c8163f02de4a92ecad72f76e2849042
diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
index e897482..19c2830 100644
--- a/cmds/atrace/atrace.cpp
+++ b/cmds/atrace/atrace.cpp
@@ -224,6 +224,11 @@
     { "pagecache",  "Page cache", 0, {
         { REQ,      "events/filemap/enable" },
     } },
+    { "memory",  "Memory", 0, {
+        { OPT,      "events/kmem/rss_stat/enable" },
+        { OPT,      "events/kmem/ion_heap_grow/enable" },
+        { OPT,      "events/kmem/ion_heap_shrink/enable" },
+    } },
 };
 
 struct TracingVendorCategory {