Force ComplexPath if any part of the node requires it everywhere

Extent the logic that upgrades text runs to the complex path if any part
of the RenderText needs it. This expands the fix in r183104 to apply
anywhere.

BUG=420593
R=pdr@chromium.org

Review URL: https://codereview.chromium.org/639553002

git-svn-id: svn://svn.chromium.org/blink/trunk@183372 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add layout tests for seeks to zero on streaming sources.

Adds testing for the Chrome side patch:
https://codereview.chromium.org/621573002

BUG=412562
TEST=all tests!

Review URL: https://codereview.chromium.org/615193004

git-svn-id: svn://svn.chromium.org/blink/trunk@183373 bbb929c8-8fbe-4397-9dbb-9b2b20218538