as discussed with metrics team, the idea here is to have a set of sparse histograms that cover the following events:

 - Launch
 - Crash
 - Killed

For utility processes, based on the hash of the process name. The hashes will be resolved server-side based on enums.xml additions. Hopefully we can keep this manageable.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/edb011f9c5419adf438c27747ff1e53e78ea7782

commit edb011f9c5419adf438c27747ff1e53e78ea7782
Author: Will Harris <wfh@chromium.org>
Date: Fri Jun 01 20:28:44 2018

Set a consistent browser child process name for metrics.

Add new "metrics name" which is non-localized and will be used for
recording metrics for child processes. The name is taken from the
mojo service name for mojo processes, or can be custom set.

BUG=767906

Change-Id: Ibcfa314fe4c475256f76a4369d17e63e32050195
Reviewed-on: https://chromium-review.googlesource.com/1072789
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563777}
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/browser_child_process_host_impl.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/browser_child_process_host_impl.h
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/mojo_sandbox_browsertest.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/power_monitor_browsertest.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/service_manager/service_manager_context.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/utility_process_host.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/utility_process_host.h
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/browser/utility_process_host_browsertest.cc
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/public/browser/browser_child_process_host.h
[modify] https://crrev.com/edb011f9c5419adf438c27747ff1e53e78ea7782/content/public/browser/child_process_data.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3e343ca4b797fa9b48a510e3f419fd1f2ceaf52d

commit 3e343ca4b797fa9b48a510e3f419fd1f2ceaf52d
Author: Varun Khaneja <vakh@chromium.org>
Date: Wed Jun 06 23:06:22 2018

unrar: Use CHECK(false) instead of explicitly terminating process.

No change to README.chromium required since it already contains:
- Replace exceptions with terminating the current process. Guarded with the
  macro UNRAR_NO_EXCEPTIONS.

R=wfh

Bug: 750327,847635,767906
Change-Id: Ie5efe8b637f87647ea2972c115a2ac2464ef793d
Reviewed-on: https://chromium-review.googlesource.com/1081434
Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565082}
[modify] https://crrev.com/3e343ca4b797fa9b48a510e3f419fd1f2ceaf52d/third_party/unrar/src/errhnd.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ffe7466328c1957fc9c536d62c0f5327224e1ff1

commit ffe7466328c1957fc9c536d62c0f5327224e1ff1
Author: Will Harris <wfh@chromium.org>
Date: Thu Jun 07 05:16:29 2018

Add tests for BrowserChildProcessObserver crash notifications.

Also, add tests for launches too, since this wasn't really tested
anywhere before.

BUG=767906

Change-Id: Ibdd39584a2637986590183458ca3e1fbe7874c13
Reviewed-on: https://chromium-review.googlesource.com/1086225
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565189}
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/browser/service_worker/service_worker_version_unittest.cc
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/browser/utility_process_host_browsertest.cc
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/public/test/test_service.cc
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/public/test/test_service.h
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/public/test/test_service.mojom
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/shell/renderer/shell_content_renderer_client.cc
[modify] https://crrev.com/ffe7466328c1957fc9c536d62c0f5327224e1ff1/content/shell/utility/shell_content_utility_client.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/358519c2aedd3947ecdcf59e94c2909e4f6b52cf

commit 358519c2aedd3947ecdcf59e94c2909e4f6b52cf
Author: Will Harris <wfh@chromium.org>
Date: Tue Jun 12 20:39:35 2018

Add metrics for Utility process launches and crashes.

BUG=767906

Change-Id: I6ee1d00152a67f751f299ebc63ed912dc29aba5c
Reviewed-on: https://chromium-review.googlesource.com/1091393
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566557}
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/chrome/browser/metrics/chrome_stability_metrics_provider.cc
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/chrome/browser/metrics/chrome_stability_metrics_provider.h
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/chrome/browser/metrics/chrome_stability_metrics_provider_unittest.cc
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/components/metrics/stability_metrics_helper.cc
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/components/metrics/stability_metrics_helper.h
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/content/browser/utility_process_host.h
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/358519c2aedd3947ecdcf59e94c2909e4f6b52cf/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aefdbd8caa235f63e3d2e23516b82182b3a4fce8

commit aefdbd8caa235f63e3d2e23516b82182b3a4fce8
Author: Will Harris <wfh@chromium.org>
Date: Wed Jun 13 22:10:26 2018

Update utility process name hashes.

Due to an issue with the spreadsheet, some rows were not handling
negative enum values correctly so these values are corrected in this
CL.

In addition, the following names were also added based on metrics seen
on Canary:

util_win
chrome_printing
cdm
profile_import
file_util
patch_service
pdf_compositor

BUG=767906

Change-Id: I8b599a38f7728d35d150efb06c9d9d47a6a6685b
Reviewed-on: https://chromium-review.googlesource.com/1099366
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567012}
[modify] https://crrev.com/aefdbd8caa235f63e3d2e23516b82182b3a4fce8/tools/metrics/histograms/enums.xml

This data can be viewed on timeline using formulae e.g.

https://uma.googleplex.com/p/chrome/timeline_v2?sid=0dc2de839410fa50616c8adc87af0531 which is the top 98% of launches, plotted crashes per launch.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b92a836e9c96042ad9f9c6c413ab388553bcc52b

commit b92a836e9c96042ad9f9c6c413ab388553bcc52b
Author: Will Harris <wfh@chromium.org>
Date: Thu Jun 21 23:09:16 2018

Add a few more utility process hashes.

BUG=767906

Change-Id: I79dfb0509a1acc532a97750b4609e8bd6e3a438e
Reviewed-on: https://chromium-review.googlesource.com/1110356
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569419}
[modify] https://crrev.com/b92a836e9c96042ad9f9c6c413ab388553bcc52b/tools/metrics/histograms/enums.xml