MD-Settings: Convert users of cr:cancel to paper-icon-button-light.

R=dbeam@chromium.org,dschuyler@chromium.org
BUG=NONE
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2875733002
Cr-Commit-Position: refs/heads/master@{#473290}
7 files changed