Split out repaint code from RenderBlockFlow layout.

Currently the RenderBlockFlow layout code has a FIXME to extract some repaint
logic into a helper function. This extraction is needed for the repaintAfterLayout
work because we need to be able to call it when layout is complete.

This CL pulls the code out into a method defined in RenderObject and overridden
in RenderBlockFlow.

BUG=310398

Review URL: https://codereview.chromium.org/110543002

git-svn-id: svn://svn.chromium.org/blink/trunk@163460 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make calls to AtomicString(const String&) explicit in css/

Make calls to AtomicString(const String&) explicit in css/ and avoid useless
conversions from String to AtomicString when possible.

This is one step towards making the AtomicString(const String&) constructor
explicit. This CL takes care only of the css/ part so that it is more
easily reviewable.

R=eseidel, abarth
BUG=323739

Review URL: https://codereview.chromium.org/100463004

git-svn-id: svn://svn.chromium.org/blink/trunk@163461 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move WebScrollbarThemeClientImpl to platform/

BUG=297477

Review URL: https://codereview.chromium.org/109403003

git-svn-id: svn://svn.chromium.org/blink/trunk@163462 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make arguments to Range methods non-optional

http://dom.spec.whatwg.org/#interface-rage
http://domparsing.spec.whatwg.org/#extensions-to-the-range-interface

Only touch methods defined by the above specs.

The added missing-arguments test passes in Firefox Nightly, IE11
Release Preview and Opera 12.16, so there ought to be fairly little
Web content depending on the old behavior.

BUG=325922

Review URL: https://codereview.chromium.org/108063005

git-svn-id: svn://svn.chromium.org/blink/trunk@163463 bbb929c8-8fbe-4397-9dbb-9b2b20218538