Simplify HTMLDocumentParser a little

!isDocumentFragment() was already asserted above.

Might as well combine the ifs and make the comment one line.

Review URL: https://codereview.chromium.org/246633005

git-svn-id: svn://svn.chromium.org/blink/trunk@172333 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move flexbox-with-stretch-layout.html from PerformanceTests/ to PerformanceTests/layout/. This fixes the bug caused by the page referencing "../resources/runner.js" script whereas resources folder was in the same directory as flexbox-with-stretch-layout.html.
BUG=365599

Review URL: https://codereview.chromium.org/248443002

git-svn-id: svn://svn.chromium.org/blink/trunk@172334 bbb929c8-8fbe-4397-9dbb-9b2b20218538