All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=867438

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=77654d8a51b1aeb0ee145c51c60d07bb0f4c97e485c7caf1733677b1e3425d46


Bot(s) for this bug's original alert(s):

android-nexus5X
android-one

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/126e2f6da40000

sullivan@ could you reassing it as appropriate? I'm not quite familiar with perf triage. Thanks!

Removing owner so pinpoint can set it.

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/126e2f6da40000

VR: Ensuring consistency of events when transitioning to 2D UI by acondor@chromium.org
https://chromium.googlesource.com/chromium/src/+/0d7abffcc3f8d9f81bd3dea8a2aea9b70bbb390b
26.1 → 13.35 (-12.75)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

 Issue 867439  has been merged into this issue.

 Issue 867673  has been merged into this issue.

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/119dc0ffa40000

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/119dc0ffa40000

All of the runs failed. The most common error (10/20 runs) was:
BuildError: Build failed: BUILD_FAILURE

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/16fbdd40640000

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/16fbdd40640000

All of the runs failed. The most common error (1/20 runs) was:
IOError: [Errno 2] No such file or directory: '/b/s/w/it9Z23f7/tmpioXIlWtelemetry/histograms.json'

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14fcf14fa40000

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/14fcf14fa40000

All of the runs failed. The most common error (1/20 runs) was:
IOError: [Errno 2] No such file or directory: '/b/s/w/itRgcuFI/tmpzrZ4f9telemetry/histograms.json'

Could someone point me out if I'm running the appropriate metric? https://pinpoint-dot-chromeperf.appspot.com/job/11750d84640000
The original metric seems to be gone.

I was able to fix the regression with a patch https://pinpoint-dot-chromeperf.appspot.com/job/14bfb3c8640000

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/02cd150c24de8bdebb14d88c1a144b921a47756f

commit 02cd150c24de8bdebb14d88c1a144b921a47756f
Author: Aldo Culquicondor <acondor@chromium.org>
Date: Mon Aug 13 16:21:43 2018

Add default source to the MotionEventSynthetizer

Having an undefined source triggers warnings in the logs.
SOURCE_CLASS_POINTER is the minimal requirement for producing
touch events, and it is general enough. Passing the source as
an argument to `inject` was causing perf regressions.

BUG= 855626 ,  867438 

Change-Id: I05458c9c98776a2af99b570aba5760adfd0381d5
Reviewed-on: https://chromium-review.googlesource.com/1167207
Commit-Queue: Aldo Culquicondor <acondor@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582606}
[modify] https://crrev.com/02cd150c24de8bdebb14d88c1a144b921a47756f/chrome/android/java/src/org/chromium/chrome/browser/vr/AndroidUiGestureTarget.java
[modify] https://crrev.com/02cd150c24de8bdebb14d88c1a144b921a47756f/content/public/android/java/src/org/chromium/content/browser/MotionEventSynthesizerImpl.java
[modify] https://crrev.com/02cd150c24de8bdebb14d88c1a144b921a47756f/content/public/android/java/src/org/chromium/content/browser/SyntheticGestureTarget.java
[modify] https://crrev.com/02cd150c24de8bdebb14d88c1a144b921a47756f/content/public/android/java/src/org/chromium/content_public/browser/MotionEventSynthesizer.java