Rewrite LayoutNG margin collapsing/floats unit tests
This patch rewrites PositionFloatFragments, CollapsingMarginsCase2WithFloats,
CollapsingMarginsCase1WithFloats and PositionFloatInsideEmptyBlocks(new).
Also it makes NGBlockLayoutAlgorithmTest to be based on RenderingTest. That
allows to use setBodyInnerHTML to set HTML representation of tests and enables
unittests to access old layout objects like FloatingObjects etc.
The tests that are being changed here are temporarily marked as DISABLED.
That's because the old tests are not fully correct. For the new float/margins
collapsing algorithm these new tests will set correct expectations and will
be enabled once the new code checked in.
BUG=635619
Review-Url: https://codereview.chromium.org/2641253002
Cr-Commit-Position: refs/heads/master@{#445900}
2 files changed
