A user reported that "On some pages, I can’t scroll to the bottom of the page using the trackpad, but I can get there with the down arrow key." This seems to be an issue with sub-pixel calculations when a scrollable <div> is nested inside another scrollable <div>.
<rdar://problem/17910241>
Created attachment 236077 [details] Patch
Comment on attachment 236077 [details] Patch I don't know much about scrolling, but wouldn't it make sense to fix those totalSize()/visibleSize() values too? It seems like we can't use them to calculate the scroll size value anymore and that could potentially cause other issues throughout the code -wherever they are used (if they are used at all)
Comment on attachment 236077 [details] Patch I think you should be able to make a layout test for this.
Comment on attachment 236077 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=236077&action=review > Source/WebCore/rendering/RenderLayer.cpp:2603 > + IntSize scrollRange = maximumScrollPosition() - minimumScrollPosition(); > + if (orientation == HorizontalScrollbar) > + return scrollRange.width(); > + > + return scrollRange.height(); The blank line makes this read awkwardly. I think ? : would be nicer.
Comment on attachment 236077 [details] Patch Why no regression test?
Comment on attachment 236077 [details] Patch Attachment 236077 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/4751358750097408 New failing tests: ietestcenter/css3/bordersbackgrounds/background-attachment-local-scrolling.htm
Created attachment 236079 [details] Archive of layout-test-results from webkit-ews-13 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-13 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Comment on attachment 236077 [details] Patch Attachment 236077 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/4914987340398592 New failing tests: ietestcenter/css3/bordersbackgrounds/background-attachment-local-scrolling.htm
Created attachment 236080 [details] Archive of layout-test-results from webkit-ews-05 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-05 Port: mac-mountainlion Platform: Mac OS X 10.8.5
Comment on attachment 236077 [details] Patch Attachment 236077 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/6105597372006400 New failing tests: ietestcenter/css3/bordersbackgrounds/background-attachment-local-scrolling.htm
Created attachment 236081 [details] Archive of layout-test-results from webkit-ews-04 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-04 Port: mac-mountainlion Platform: Mac OS X 10.8.5
(In reply to comment #6) > (From update of attachment 236077 [details]) > Why no regression test? Yes - I'm working on that now!
Created attachment 236108 [details] Patch
Committed r172160: <http://trac.webkit.org/changeset/172160>