Here are trace files for comparison. trace_new-GetStaticBitmapImage uses the proposed fix from https://chromium-review.googlesource.com/c/592249/ . Both still show the slow/fast pattern (see  issue 747159  for that), but the sync IPCs in CrRenderMain's submitFrame are reduced from three to one.

Deleted: trace_new-GetStaticBitmapImage.html 3.7 MB

trace_new-GetStaticBitmapImage.html 3.7 MB View Download

Deleted: trace_totnoalign-fastslowpattern.html 4.2 MB

trace_totnoalign-fastslowpattern.html 4.2 MB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/30ba029f1291127d6f5df4f478e9629f82609415

commit 30ba029f1291127d6f5df4f478e9629f82609415
Author: Klaus Weidner <klausw@chromium.org>
Date: Tue Aug 08 18:35:02 2017

Use bitmap creation from commit() for WebVR

The WebVR pipeline used WebGLRenderingContextBase's GetImage which
required a total of three synchronous IPC calls to the GPU process.

Instead, reuse the logic from the commit() method, this needs just
a single SyncChannel::Send. Also, this made it possible to remove
additional flushes that had been needed to work around synchronization
issues.

BUG= 750286 
R=bajones@chromium.org

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: Ia27766575c183212aa59c52e86bfd1f619763c73
Reviewed-on: https://chromium-review.googlesource.com/592249
Reviewed-by: Brandon Jones <bajones@chromium.org>
Commit-Queue: Klaus Weidner <klausw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492707}
[modify] https://crrev.com/30ba029f1291127d6f5df4f478e9629f82609415/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
[modify] https://crrev.com/30ba029f1291127d6f5df4f478e9629f82609415/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
[modify] https://crrev.com/30ba029f1291127d6f5df4f478e9629f82609415/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h

This is included in today's canary 62.0.3180.0. Adjusting milestone to M62 since I think there's no current plans to cherrypick this to M61, but we may want to revisit this in case it does improve performance sufficiently.