Move memory management code into separate class for future reuse.

base/debug/activity_analyzer.cc

Index: base/debug/activity_analyzer.cc
diff --git a/base/debug/activity_analyzer.cc b/base/debug/activity_analyzer.cc
index 79d513b5af6c61a64b2ab4d0188c51db8fe2b329..4254df03a0191a81eaf12b88c6e94a3ceff30d08 100644
--- a/base/debug/activity_analyzer.cc
+++ b/base/debug/activity_analyzer.cc
@@ -90,7 +90,7 @@ void GlobalActivityAnalyzer::PrepareAllAnalyzers() {
   while ((ref = allocator_iterator_.GetNext(&type)) != 0) {
     switch (type) {
       case GlobalActivityTracker::kTypeIdActivityTracker:
-      case GlobalActivityTracker::kTypeIdActivityTrackerFree:
+      case ~GlobalActivityTracker::kTypeIdActivityTracker:

[Alexei Svitkine (slow), 2016/10/13 19:23:20]

Nit: Can this also use the helper function? You can probably change the switch
to an if in that case.

Or make another helper in GlobalActivityTracker that asks if it's of that type
and inline the logic there, so the details are contained in that code.

[bcwhite, 2016/10/13 19:35:13]

How about if I just make the class take a "free type" constructor parameter,
instead?  The free type can be defined in the enum as anything (including
free_type=~type).  Helper methods go away and everything is clean again.  Cost
is one more const uint32_t member variable.

         // Free or not, add it to the list of references for later analysis.
         tracker_references_.insert(ref);
         break;