createFragmentFromMarkupWithContext() calls |hasEditableLevel()| for detached document, see https://bugs.webkit.org/show_bug.cgi?id=60620 introduced it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9ceffba8b9056e7a125f5a9fd8eb803816315df7

commit 9ceffba8b9056e7a125f5a9fd8eb803816315df7
Author: xiaochengh <xiaochengh@chromium.org>
Date: Fri Nov 25 00:50:11 2016

Ensure active document for hasEditableLevel

This patch makes hasEditableStyle and hasRichlyEditableStyle return false
directly if document is inactive, because nothing in an inactive document
is editable.

The ultimate goal is to ensure that no code path inspects editable styles
in an inactive document, which will be done by subsequent patches.

BUG= 667681 

Review-Url: https://codereview.chromium.org/2530753002
Cr-Commit-Position: refs/heads/master@{#434414}

[modify] https://crrev.com/9ceffba8b9056e7a125f5a9fd8eb803816315df7/third_party/WebKit/Source/core/editing/EditingUtilities.cpp

Further actions are paused, as we need to discuss the future of -webkit-user-modify.