The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0e466ff6c591b29e2e97bda6a5841f9180401781

commit 0e466ff6c591b29e2e97bda6a5841f9180401781
Author: Rune Lillesveen <futhark@chromium.org>
Date: Fri Jan 12 06:33:50 2018

Don't create MediaQuerySet for style elements without media.

Also, check if the MediaQuerySet contains anything before forcing an
active style update on media query affecting value changes. Always
creating a MediaQuerySet for style elements made us recollect active
stylesheets in every scope containing style elements. In particular, if
a media query in the document scope caused us to update active style in
the document scope, we also triggered an active stylesheet update in
all shadow scopes containing a style element.

Bug:  801108 
Change-Id: I06246b8c18507560c5d7c45b5a73ddd74f6dcb0f
Reviewed-on: https://chromium-review.googlesource.com/860925
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528893}
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/CSSStyleSheet.cpp
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/CSSStyleSheet.h
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/StyleElement.cpp
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/StyleEngineTest.cpp
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/StyleSheet.h
[modify] https://crrev.com/0e466ff6c591b29e2e97bda6a5841f9180401781/third_party/WebKit/Source/core/css/TreeScopeStyleSheetCollection.cpp