We should probably merge https://chromium.googlesource.com/chromium/blink/+/3b062d8c310875be0fe6f26a89e2592104944e83 Used to only recognize 0x20 as a separator for attribute selector matching values in space separated lists. Now recognizes 0x09, 0x0a, 0x0c, 0x0d, and 0x20 as separators.
*** This bug has been marked as a duplicate of bug 115954 ***