Vulkan: Make Resource's updateSerial private. This simplifies the API from the calling resource classes. This method is called internally instead. beginWriteResource and appendWriteResource both call updateSerial internally. Additionally this removes hasStartedRenderPass and instead returns a boolean from appendToStartedRenderPass indicating success. Bug: angleproject:2539 Change-Id: Idcf72e6a80dde90e83dabc64644051bb536c6b12 Reviewed-on: https://chromium-review.googlesource.com/1066554 Reviewed-by: Frank Henigman <fjhenigman@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>