Hm, but isn't that code only run in the browser process? I wouldn't expect PreSandboxStartup to run in renderers.

MainDelegate code generally runs on all processes. I don't know specifically about PreSandboxStartup though, but from the sound of the name, maybe it should *only* run in child processes..?

Yeah actually looking at content_main_runner, it runs in all processes, and the name is pretty irrelevant on Linux because the sandbox is not actually started in content_main_runner anyway (so PreSandboxStartup is immediately followed by SandboxInitialized without anything happening inbetween).

Although that code does run in browser and renderer processes, I was to hasty about calling that out as the location of the problem. At that point the process type is actually correct (it needs to be, otherwise setting up the renderer signal pipe wouldn't work).

Predominantly the problem is that we currently mark single process crashes with "browser", not "webview". Almost none of the observed webview crashes are in multiprocess mode (I guess not many N users have enabled it) so the lack of renderer crashes is almost entirely down to the fact that there are almost no multiprocess crashes.

Apart from the multiprocess issue, there's a secondary problem with ptype, which is that it is regexed out of the logs, and the match is not necessarily in the microdump that ends up being symbolized.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e

commit 90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e
Author: tobiasjs <tobiasjs@chromium.org>
Date: Mon Apr 10 17:15:44 2017

aw: Fix multiprocess flag usage

Stop using kSingleProcess, which does not mean what we think it means.
Pass the correct webview process type to breakpad, so that microdumps
contain the correct information.

BUG= 708773 

Review-Url: https://codereview.chromium.org/2806733002
Cr-Commit-Position: refs/heads/master@{#463302}

[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/android_webview/browser/aw_browser_main_parts.cc
[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/android_webview/browser/aw_content_browser_client.cc
[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/android_webview/common/crash_reporter/aw_microdump_crash_reporter.cc
[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/android_webview/java/src/org/chromium/android_webview/AwSwitches.java
[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/android_webview/lib/main/aw_main_delegate.cc
[modify] https://crrev.com/90bce3cf40ac6f6cfaf1e3b742bf47f86f2d4e6e/components/crash/content/app/breakpad_linux.cc

This bug requires manual review: We are only 13 days from stable.
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), bhthompson@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot