build(browserstack): initial setup

Closes #4941

scripts/ci/after-script.sh

@@ -8,6 +8,9 @@ echo '*******************'
 if [ "$MODE" = "saucelabs" ]; then
   ./scripts/sauce/sauce_connect_teardown.sh
 fi
+if [ "$MODE" = "browserstack" ]; then
+  ./scripts/browserstack/teardown_tunnel.sh
+fi
 
 
 echo '---------------------'

scripts/ci/build_and_test.sh

@@ -10,7 +10,7 @@ cd $SCRIPT_DIR/../..
 
 if [ "$MODE" = "dart_experimental" ]; then
   ${SCRIPT_DIR}/build_$MODE.sh
-elif [ "$MODE" = "saucelabs" ]; then
+elif [ "$MODE" = "saucelabs" ] || [ "$MODE" = "browserstack" ] ; then
   ${SCRIPT_DIR}/test_$MODE.sh
 elif [ "$MODE" = "lint" ]; then
   ./node_modules/.bin/gulp static-checks

scripts/ci/test_browserstack.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+
+echo =============================================================================
+# go to project dir
+SCRIPT_DIR=$(dirname $0)
+cd $SCRIPT_DIR/../..
+
+./scripts/browserstack/start_tunnel.sh
+./scripts/browserstack/waitfor_tunnel.sh
+./node_modules/.bin/gulp build.js.dev
+./node_modules/.bin/gulp test.unit.js.browserstack/ci