[CSSRegions] ASSERTION FAILED: !m_regionsInvalidated in RenderFlowThread::regionAtBlockOffset
https://bugs.webkit.org/show_bug.cgi?id=129371

Source/WebCore:

Reviewed by Andrei Bucur.

regionAtBlockOffset method is meant to be used after the flow thread validated
its region chain, otherwise we cannot rely on regionAtBlockOffset to determine correctly
the target region based on the offset in flow thread coordinates.

When the video element is collected in a named flow and displayed in a region, we ensure
that the region's decorations are taken into account to properly position the video.
However, we have to do that only if the named flow regions are validated.

I changed the method cachedRegionForCompositedLayer to check only the "cached" region
for a layer and not update the layer to region mappings before returning the region.
Because method cachedRegionForCompositedLayer does not update the region - layer mappings,
the code does not call regionAtBlockOffset in situations where the region chain is not validated yet.

Test: compositing/regions/video-in-overflow-region.html

* rendering/RenderFlowThread.cpp:
(WebCore::RenderFlowThread::getLayerListForRegion): Make it a getter that relies on
cached information and refrain from updating the mappings. Make it const too.
(WebCore::RenderFlowThread::cachedRegionForCompositedLayer):
* rendering/RenderFlowThread.h:

LayoutTests:

Reviewed Andrei Bucur.


* compositing/regions/video-in-overflow-region-expected.txt: Added.
* compositing/regions/video-in-overflow-region.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@164858 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Add hiDPI support to DumpRenderTree/WebKitTestRunner without the need of reloading the test case.
https://bugs.webkit.org/show_bug.cgi?id=129438

Reviewed by Simon Fraser.

'hidpi-' prefixed test cases now trigger 2x scale factor on the testing
offscreen window. It makes testing subpixel rendering and positioning possible.

Both the offscreen window's and WebKit's scaling are set accordingly.

Tools:

* DumpRenderTree/mac/DumpRenderTree.mm:
(createWebViewAndOffscreenWindow): unrelated cleanup.
(destroyWebViewAndOffscreenWindow): unrelated cleanup.
(dumpRenderTree):
(changeOffscreenWindowScaleIfNeeded):
(runTest):
* DumpRenderTree/mac/DumpRenderTreeWindow.h:
* DumpRenderTree/mac/DumpRenderTreeWindow.mm:
(-[DumpRenderTreeWindow initWithContentRect:styleMask:backing:defer:]): cleanup.
* WebKitTestRunner/PlatformWebView.h:
* WebKitTestRunner/TestInvocation.cpp:
(WTR::changeOffscreenWindowScaleIfNeeded):
(WTR::TestInvocation::invoke):
* WebKitTestRunner/mac/PlatformWebViewMac.mm:
(WTR::PlatformWebView::changeOffscreenWindowScaleIfNeeded):

LayoutTests:

* fast/borders/hidpi-simple-hairline-border-painting-expected.html: Added.
* fast/borders/hidpi-simple-hairline-border-painting.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@164859 268f45cc-cd09-0410-ab3c-d52691b4dbfc