diff --git a/go.sum b/go.sum
index 9be6f3c..09a0294 100644
--- a/go.sum
+++ b/go.sum
@@ -354,6 +354,12 @@
 github.com/golang/protobuf v1.3.4/go.mod h1:vzj43D7+SQXF/4pzW/hwtAqwc6iTitCiVSaWz5lYuqw=
 github.com/golang/protobuf v1.3.5 h1:F768QJ1E9tib+q5Sc8MkdJi1RxLTbRcTf8LJV56aRls=
 github.com/golang/protobuf v1.3.5/go.mod h1:6O5/vntMXwX2lRkT1hjjk0nAC1IDOTvTlVgjlRvqsdk=
+github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8=
+github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:xKAWHe0F5eneWXFV3EuXVDTCmh+JuBKY0li0aMyXATA=
+github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs=
+github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
+github.com/golang/protobuf v1.4.0 h1:oOuy+ugB+P/kBdUnG5QaMXSIyJ1q38wWSojYCb3z5VQ=
+github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/snappy v0.0.0-20170215233205-553a64147049/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/golang/snappy v0.0.1 h1:Qgr9rKW7uDUkrbSmQeiDsGa8SjGyCOGtuasMWwvp2P4=
@@ -906,6 +912,8 @@
 go.chromium.org/luci v0.0.0-20200410032135-d9943f49d18d/go.mod h1:MIQewVTLvOvc0UioV0JNqTNO/RspKFS0XEeoKrOxsdM=
 go.chromium.org/luci v0.0.0-20200410225717-28d3dd74d42a h1:2lje64zFOjYVzk9oLKB4bBv6bxlRj8OwVdLVRdJ/+OM=
 go.chromium.org/luci v0.0.0-20200410225717-28d3dd74d42a/go.mod h1:MIQewVTLvOvc0UioV0JNqTNO/RspKFS0XEeoKrOxsdM=
+go.chromium.org/luci v0.0.0-20200414043739-5248f578d95a h1:wsowxqNeOP6su/U9Ru5ej92YdsJkzDJ7Hso+rZorIEM=
+go.chromium.org/luci v0.0.0-20200414043739-5248f578d95a/go.mod h1:MIQewVTLvOvc0UioV0JNqTNO/RspKFS0XEeoKrOxsdM=
 go.etcd.io/bbolt v1.3.2/go.mod h1:IbVyRI1SCnLcuJnV2u8VeU0CEYM7e686BmAb1XKL+uU=
 go.mongodb.org/mongo-driver v1.1.0/go.mod h1:u7ryQJ+DOzQmeO7zB6MHyr8jkEQvC8vH7qLUO4lqsUM=
 go.opencensus.io v0.20.1/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=
@@ -1013,6 +1021,8 @@
 go.skia.org/infra v0.0.0-20200412015334-dae60125f8fd/go.mod h1:WG1Bk7K8KrCgdx6xxehaRNQzHQVKcIcjPDwyuiSrFJQ=
 go.skia.org/infra v0.0.0-20200412052613-78563fc49947 h1:8zrKuGWUOdf6IFiY0StvVYQCNxvKscAgOTD7vS2+jx4=
 go.skia.org/infra v0.0.0-20200412052613-78563fc49947/go.mod h1:PEv9Qk1zv4L2xhADXsoE08UT7OBgqu7X++4a54NHLw8=
+go.skia.org/infra v0.0.0-20200413140145-10056a16e08a h1:c31zoQW2Q0CfQ/4E1gtLl9Ik29raTdfcc3CN3c1i7OU=
+go.skia.org/infra v0.0.0-20200413140145-10056a16e08a/go.mod h1:+8GkT+GM09MTTAWOdImHEJ7OHSSNL+NG+r7IeaPzAV4=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
@@ -1233,6 +1243,8 @@
 golang.org/x/sys v0.0.0-20200408040146-ea54a3c99b9b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200409092240-59c9f1ba88fa h1:mQTN3ECqfsViCNBgq+A40vdwhkGykrrQlYe3mPj6BoU=
 golang.org/x/sys v0.0.0-20200409092240-59c9f1ba88fa/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200413165638-669c56c373c4 h1:opSr2sbRXk5X5/givKrrKj9HXxFpW2sdCiP8MJSKLQY=
+golang.org/x/sys v0.0.0-20200413165638-669c56c373c4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.0.0-20160726164857-2910a502d2bf/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -1384,6 +1396,8 @@
 golang.org/x/tools v0.0.0-20200410194907-79a7a3126eef/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20200413015812-1f08ef6002a8 h1:1TnYi6m8UoNpEKS1wxgR8GcHPe2YDgYoDjAedVuX+Q0=
 golang.org/x/tools v0.0.0-20200413015812-1f08ef6002a8/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
+golang.org/x/tools v0.0.0-20200414032229-332987a829c3 h1:Z68UA+HA9shnGhQbAFXKqL1Rk/tfiTHJ57bNm/MUL/A=
+golang.org/x/tools v0.0.0-20200414032229-332987a829c3/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/xerrors v0.0.0-20190410155217-1f06c39b4373/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20190513163551-3ee3066db522/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -1518,6 +1532,8 @@
 google.golang.org/genproto v0.0.0-20200409111301-baae70f3302d/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200410110633-0848e9f44c36 h1:QGM8iDIfHwTRMruKa7+aKDNRMQcWKeS6LDhdMiucYCE=
 google.golang.org/genproto v0.0.0-20200410110633-0848e9f44c36/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
+google.golang.org/genproto v0.0.0-20200413115906-b5235f65be36 h1:j7CmVRD4Kec0+f8VuBAc2Ak2MFfXm5Q2/RxuJLL+76E=
+google.golang.org/genproto v0.0.0-20200413115906-b5235f65be36/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/grpc v1.17.0/go.mod h1:6QZJwpn2B+Zp71q/5VxRsJ6NXXVCE5NRUHRo+f3cWCs=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
 google.golang.org/grpc v1.20.1 h1:Hz2g2wirWK7H0qIIhGIqRGTuMwTE8HEKFnDZZ7lm9NU=
@@ -1540,6 +1556,12 @@
 google.golang.org/grpc v1.28.0/go.mod h1:rpkK4SK4GF4Ach/+MFLZUBavHOvF2JJB5uozKKal+60=
 google.golang.org/grpc v1.28.1 h1:C1QC6KzgSiLyBabDi87BbjaGreoRgGUF5nOyvfrAZ1k=
 google.golang.org/grpc v1.28.1/go.mod h1:rpkK4SK4GF4Ach/+MFLZUBavHOvF2JJB5uozKKal+60=
+google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
+google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
+google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
+google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
+google.golang.org/protobuf v1.21.0 h1:qdOKuR/EIArgaWNjetjgTzgVTAZ+S/WXVrq9HW9zimw=
+google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=