Doing some rendertrace logging on the peak in the settings app showed that the displayport being requested was sometimes 540 pixels wide even though the page was only 360 pixels wide. Turns out GetExpandedScrollableRect doesn't bother to convert the composition bounds from a ScreenRect to a CSSRect. The composition bounds isn't always correct (bug 935219) but even so expanding the scrollable rect by a ScreenRect composition bounds is wrong.
Created attachment 8348953 [details] [diff] [review] Patch This fixes the issue, but I need to test it more to ensure there aren't any other bad side-effects.
Assignee: nobody → bugmail.mozilla
Attachment #8348953 - Flags: review+
https://hg.mozilla.org/integration/b2g-inbound/rev/e1b8a4d97075 Requesting uplift to 1.3. There are no user-visible bad effects from this bug, but I suspect it might result in wasted memory usage because the displayport is larger than it should be. I'm not actually sure if the texture that gets created is larger or not though.
blocking-b2g: --- → 1.3?
Doh. This is actually a regression introduced very recently in bug 949404.
Status: NEW → RESOLVED
Last Resolved: 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla29
status-firefox29: affected → fixed
Comment on attachment 8348953 [details] [diff] [review] Patch [Approval Request Comment] Bug caused by (feature/regressing bug #): bug 949404 User impact if declined: panning around on some pages is very janky in metrofox (see bug 951751) Testing completed (on m-c, etc.): locally Risk to taking this patch (and alternatives if risky): low risk, very obvious fix for the regression. affects only b2g and metro String or IDL/UUID changes made by this patch: none
Attachment #8348953 - Flags: approval-mozilla-aurora?
Attachment #8348953 - Flags: approval-mozilla-aurora? → approval-mozilla-aurora+
status-b2g-v1.3: affected → fixed
status-firefox28: affected → fixed
Already in 1.3 per comment 7, so clearing nom.
blocking-b2g: 1.3? → ---
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