Adds tumblr to social share component (#499)
Adds tumblr to social share component (#499)


ampproject/amp-by-example,camelburrito/amp-by-example,ampproject/amp-by-example,ampproject/amp-by-example,camelburrito/amp-by-example,camelburrito/amp-by-example,camelburrito/amp-by-example,ampproject/amp-by-example