KHTML/Webkit/Blink are all LGPL and/or BSD, which is specifically not restrictive for linking to.
Many people assume all of Linux is GPL. I say "special case" because not everyone knows the most-linked-to stuff isn't.
? Android is, AFAIK, completely permissively licensed except for the kernel, and KHTML/WebKit/Blink are BSD/LGPL; what would be special about them in this context?