ASSERTION FAILED: x2 >= x1 in WebCore::RenderObject::drawSolidBoxSide

In some cases when a negative margin and a positive padding are applied
together to the right and/or left side of the box, the logical width of
the borders can be set to a negative value, making the assertion fire.
The fix checks if the width or height of the box is negative, and if so,
it will not display the borders and shadows of the box.

This is a backport from WebKit r167351. Patch by Martin Hodovan and reviewed by Darin Adler.

R=schenney@chromium.org
BUG=364797

Review URL: https://codereview.chromium.org/242903002

git-svn-id: svn://svn.chromium.org/blink/trunk@171987 bbb929c8-8fbe-4397-9dbb-9b2b20218538
HTML Imports: Force imports always stay standard mode.

Implement https://www.w3.org/Bugs/Public/show_bug.cgi?id=24349

TEST=import-mode-standard.html, import-mode-quirks.html
R=adamk@chromium.org, esprehn@chromium.org
BUG=343705

Review URL: https://codereview.chromium.org/243873002

git-svn-id: svn://svn.chromium.org/blink/trunk@171988 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Don't always repaint on zIndex change

If zIndex of a composited layer changes and there is no other conditions
triggering repaint, we should not repaint the layer.

Now treat zIndex change like opacity change about repainting.

BUG=364636
TEST=reuse existing compositing/repaint/should-not-repaint-composited-descendants.html

Review URL: https://codereview.chromium.org/240253007

git-svn-id: svn://svn.chromium.org/blink/trunk@171989 bbb929c8-8fbe-4397-9dbb-9b2b20218538