Ensure that warn! output is visible in client outputs.

[glennw]

No description provided.

[kvark]

I don't think it's necessarily a responsibility of WR. log crate defines standard ways to process the output, and one casual example of the consumer is env_logger. Servo hooks up to the log stream as well.

[glennw]

There's an existing bug (from @nical I think) about providing an interface for C++ clients to access a logging stream (perhaps via callback). This is probably related to that.

[nical]

In gecko we have various ways to log warnings. The one that I am interested in having some plumbing for in webrender is the gfxCriticalError/gfxCriticalNote that saves the log in the crash reports. We tend to use it sparingly, only in places where we are likely to crash soon and the logged information would helps with investigating the issue. It is super useful.

[kvark]

@nical sounds good. Could you create a Bugzilla item for this?

[nical]

There we go: https://bugzilla.mozilla.org/show_bug.cgi?id=1399389

[staktrace]

See also https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Gecko_Logging#Rust

[JerryShih]

I have some updates for this in https://bugzilla.mozilla.org/show_bug.cgi?id=1399389.

[gw3583]

The associated bugzilla bugs are fixed.