[WK2] Frameset frames are not scrollable after loading (and should be)
​https://bugs.webkit.org/show_bug.cgi?id=134151
<rdar://problem/17403365>
Reviewed by Dan Bates.
Source/WebCore:
When loading a <frameset>, we could end up with an empty non-fast-scrollable
region for the main frame, because after the initial frameset document layout,
nothing updated the non-fast scrollable region as the subframes added their
scrollable areas to the the main frame's scrollable area set.
Fix by having addScrollableArea() and removeScrollableArea() trigger an update
of the non-fast scrollable region.
Test: platform/mac-wk2/tiled-drawing/scrolling/frames/frameset-frame-scrollability.html
page/FrameView.cpp:
(WebCore::FrameView::addScrollableArea):
(WebCore::FrameView::removeScrollableArea):
(WebCore::FrameView::scrollableAreaSetChanged):
page/FrameView.h:
LayoutTests:
Frameset test that dumps the scrolling tree.
platform/mac-wk2/tiled-drawing/scrolling/frames/frameset-frame-scrollability.html: Added.
platform/mac-wk2/tiled-drawing/scrolling/frames/resources/scrollable-page.html: Added.