Remove unnecessary paintContainer parameter from addFocusRingRects

- Remove the parameter;
- Move RenderObject::addChildFocusRingRects into RenderLayerModelObject
  so that the layerQuads can be mapped by 'this' without the help of
  paintContainer;
- Don't check paintInvalidationContainer in
  RenderInline::addFocusRingRects. The original check and comment
  don't make sense. The element having outline:auto invalidates and
  paints the whole focus ring. The area of the whole focus ring is
  included in the visual overflow of the element.

TEST=existing focus-ring and outline:auto tests

Review URL: https://codereview.chromium.org/711493004

git-svn-id: svn://svn.chromium.org/blink/trunk@185242 bbb929c8-8fbe-4397-9dbb-9b2b20218538