The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7a4cc8d341b50e4f51c73ec408f038940f38c6b0

commit 7a4cc8d341b50e4f51c73ec408f038940f38c6b0
Author: yuzus <yuzus@chromium.org>
Date: Mon Apr 11 03:41:57 2016

Move shadowCascadeOrder to Document from StyleEngine

This CL moves shadowCascadeOrder function from StyleEngine to Document, so that the function can be called more universally without including StyleEngine header.
The change also makes sense because the shadowCascadingOrder is defined per document, not per styleengine.
See the ShadowDOM Cascade Order discussion here: https://github.com/w3c/webcomponents/issues/316

BUG= 601716 

Review URL: https://codereview.chromium.org/1869773004

Cr-Commit-Position: refs/heads/master@{#386329}

[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/dom/Document.cpp
[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/dom/Document.h
[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/dom/Element.cpp
[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/dom/StyleEngine.cpp
[modify] https://crrev.com/7a4cc8d341b50e4f51c73ec408f038940f38c6b0/third_party/WebKit/Source/core/dom/StyleEngine.h