Bug 82408

Summary: [chromium] Send wheel events to main thread even if we think nothing is scrollable
Product: WebKit Reporter: James Robinson <jamesr>
Component: New BugsAssignee: James Robinson <jamesr>
Status: RESOLVED FIXED    
Severity: Normal CC: enne, nduca, webkit.review.bot
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch none

Description James Robinson 2012-03-27 18:35:39 PDT
[chromium] Send wheel events to main thread even if we think nothing is scrollable
Comment 1 James Robinson 2012-03-27 18:36:12 PDT
Created attachment 134192 [details]
Patch
Comment 2 James Robinson 2012-03-27 18:37:29 PDT
This is a conservative fix for http://code.google.com/p/chromium/issues/detail?id=119984, see http://code.google.com/p/chromium/issues/detail?id=119984#c17, and meant as a quick fix.  The behavior with DidNotHandle is never worse than if we didn't have the thread, since without the thread these events would have gone to the main thread anyway.

We don't have webkit_unit_test coverage for wheel handling (which is another bug that should be fixed).
Comment 3 Adrienne Walker 2012-03-27 19:03:13 PDT
Comment on attachment 134192 [details]
Patch

R=me.  This seems quite reasonable as a short-term fix.  Sending the event to the main thread that we think won't get handled isn't going to hurt anything.

Could this happen if we get input before we finish the first commit?
Comment 4 James Robinson 2012-03-27 21:22:23 PDT
(In reply to comment #3)
> (From update of attachment 134192 [details])
> R=me.  This seems quite reasonable as a short-term fix.  Sending the event to the main thread that we think won't get handled isn't going to hurt anything.
> 
> Could this happen if we get input before we finish the first commit?

I'm not entirely sure. From the trace on the crbug there were many many frames of ScrollIgnored, not just a one-off.

I think what I'll do is add a bit of state tracking locally to compare the compositor thread results to the main thread results for each input event and see if I can repro, then backtrack from there.
Comment 5 WebKit Review Bot 2012-03-27 21:27:35 PDT
Comment on attachment 134192 [details]
Patch

Clearing flags on attachment: 134192

Committed r112363: <http://trac.webkit.org/changeset/112363>
Comment 6 WebKit Review Bot 2012-03-27 21:27:39 PDT
All reviewed patches have been landed.  Closing bug.