Fix of https://github.com/PolymerElements/paper-button/pull/180
Apparently some flat button backgrounds are made raised+not-disabled (blue) when they are actually get disabled. Spotted by scuba test (at report no. 55e88107-6691-406f-bb5e-7a332d816786)
Fix of https://github.com/PolymerElements/paper-button/pull/180 Apparently some flat button backgrounds are made raised+not-disabled (blue) when they are actually get disabled. Spotted by scuba test (at report no. 55e88107-6691-406f-bb5e-7a332d816786)