RFR: 8256955: Move includes of events.hpp out of header files

[Kim Barrett]

On Wed, 13 Jan 2021 09:51:12 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> I was making changes to events.hpp and saw that the majority of cpp files were recompiled. There are two header files that include events.hpp. I propose that we remove those usages by:
> 
> jvmci.hpp: Use a forward declaration
> collectedHeap.hpp: Move its usage to the cpp file
> 
> events.hpp also includes thread.hpp, which brings in a large portion of the HotSpot headers. So, this change is also good in that regard.

Marked as reviewed by kbarrett (Reviewer).

-------------

PR: https://git.openjdk.java.net/jdk/pull/2059