RFR: 8209802: Garbage collectors should register JFR types themselves to avoid build errors.

[Kim Barrett]

> On Sep 2, 2019, at 3:18 PM, Stefan Johansson <stefan.johansson at oracle.com> wrote:
> 
> Hi,
> 
> Please review this patch to fix JDK-8209802.
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8209802
> Webrev: http://cr.openjdk.java.net/~sjohanss/8209802/00/
> 
> Summary:
> This patch builds on the cleanup made in JDK-JDK-8230431, and adds an initialize method to G1NewTracer, that takes care of registering serializers needed for the two G1-specific constants in JFR. There is also a G1 periodic event but there is no similar way to register this from G1 code so it needs to be solved by guarding the G1 specific code in jfrPeriodic.cpp. 
> 
> Testing:
> Mach5 tier 1-3
> 
> Thanks,
> Stefan

Looks good.