Skip trampoline PutOffsetChange callbacks

In both InProcessCommandBuffer and GpuCommandBufferStub we install a
callback that sets up some state before calling
CommandExecutor::PutChanged. Since the callback is only called from
CommandBufferService::Flush, we can instead set this state before
calling it, leading to a small simplification, but more importantly
makes all PutOffsetChange callbacks identical (call into
CommandExecutor::PutChanged directly), which will allow further
simplification.

Bug: 723770
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I515d87eac976093dc3009961b7f16806be6255d5
Reviewed-on: https://chromium-review.googlesource.com/516022
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#474800}
3 files changed