Consider merging https://chromium.googlesource.com/chromium/blink/+/ecb0f25278c990b2483ef78ed1612a5cb3cefd48 Stylesheets disabled through LinkStyle.disabled were not included in Document.styleSheets, even if they existed as CSSStyleSheet objects. Fixed LinkStyle::setDisabled so it propagates disabled state to the sheet object when present. According to the HTML5 spec, setting disabled on LinkStyle when the sheet is not present should not have any effect and getting it should return false. I did not dare to do any changes there in this CL.
*** This bug has been marked as a duplicate of bug 56932 ***