feat(build): initial SauceLabs setup

Closes #2347

scripts/sauce/sauce_connect_block.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Wait for Connect to be ready before exiting
+printf "Connecting to Sauce."
+while [ ! -f $BROWSER_PROVIDER_READY_FILE ]; do
+  printf "."
+  #dart2js takes longer than the travis 10 min timeout to complete
+  sleep .5
+done
+echo "Connected"

scripts/sauce/sauce_connect_setup.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+set -e -o pipefail
+
+# Setup and start Sauce Connect for your TravisCI build
+# This script requires your .travis.yml to include the following two private env variables:
+# SAUCE_USERNAME
+# SAUCE_ACCESS_KEY
+# Follow the steps at https://saucelabs.com/opensource/travis to set that up.
+#
+# Curl and run this script as part of your .travis.yml before_script section:
+# before_script:
+#   - curl https://gist.github.com/santiycr/5139565/raw/sauce_connect_setup.sh | bash
+
+CONNECT_URL="https://saucelabs.com/downloads/sc-4.3.8-linux.tar.gz"
+CONNECT_DIR="/tmp/sauce-connect-$RANDOM"
+CONNECT_DOWNLOAD="sc-latest-linux.tar.gz"
+
+CONNECT_LOG="$LOGS_DIR/sauce-connect"
+CONNECT_STDOUT="$LOGS_DIR/sauce-connect.stdout"
+CONNECT_STDERR="$LOGS_DIR/sauce-connect.stderr"
+
+# Get Connect and start it
+mkdir -p $CONNECT_DIR
+cd $CONNECT_DIR
+curl $CONNECT_URL -o $CONNECT_DOWNLOAD 2> /dev/null 1> /dev/null
+mkdir sauce-connect
+tar --extract --file=$CONNECT_DOWNLOAD --strip-components=1 --directory=sauce-connect > /dev/null
+rm $CONNECT_DOWNLOAD
+
+SAUCE_ACCESS_KEY=`echo $SAUCE_ACCESS_KEY | rev`
+
+ARGS=""
+
+# Set tunnel-id only on Travis, to make local testing easier.
+if [ ! -z "$TRAVIS_JOB_NUMBER" ]; then
+  ARGS="$ARGS --tunnel-identifier $TRAVIS_JOB_NUMBER"
+fi
+if [ ! -z "$BROWSER_PROVIDER_READY_FILE" ]; then
+  ARGS="$ARGS --readyfile $BROWSER_PROVIDER_READY_FILE"
+fi
+
+
+echo "Starting Sauce Connect in the background, logging into:"
+echo "  $CONNECT_LOG"
+echo "  $CONNECT_STDOUT"
+echo "  $CONNECT_STDERR"
+sauce-connect/bin/sc -u $SAUCE_USERNAME -k $SAUCE_ACCESS_KEY $ARGS \
+  --logfile $CONNECT_LOG 2> $CONNECT_STDERR 1> $CONNECT_STDOUT &