Edge passes
Firefox 51.0a1 (2016-08-12) passes

Review in https://codereview.chromium.org/2414683002/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f903f01899c880f15af678b6e44404a7d9b1735f

commit f903f01899c880f15af678b6e44404a7d9b1735f
Author: karlo <karlo@opera.com>
Date: Thu Nov 03 14:06:40 2016

Make offsetTop/Left handle a relative positioned inline offsetParent correctly.

offsetTop and offsetLeft happily ignored the fact that offsetParent could
be a relative positioned inline.

I used the opportunity to change some variable names in
LayoutBoxModelObject::adjustedPositionRelativeTo() in order to hopefully
make it clearer what's going on.

BUG= 638184 

Review-Url: https://codereview.chromium.org/2414683002
Cr-Commit-Position: refs/heads/master@{#429571}

[add] https://crrev.com/f903f01899c880f15af678b6e44404a7d9b1735f/third_party/WebKit/LayoutTests/fast/inline/inline-offsetLeft-relpos-expected.txt
[add] https://crrev.com/f903f01899c880f15af678b6e44404a7d9b1735f/third_party/WebKit/LayoutTests/fast/inline/inline-offsetLeft-relpos.html
[modify] https://crrev.com/f903f01899c880f15af678b6e44404a7d9b1735f/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
[modify] https://crrev.com/f903f01899c880f15af678b6e44404a7d9b1735f/third_party/WebKit/Source/core/layout/LayoutInline.cpp
[modify] https://crrev.com/f903f01899c880f15af678b6e44404a7d9b1735f/third_party/WebKit/Source/core/layout/LayoutInline.h