Meta: Add a flag to WPT.sh to run Ladybird headlessly

We have more work to do before we can run WPT headlessly by default
(i.e. handling alerts). But for now, we can run it headlessly locally
with the --headless flag.

Meta/WPT.sh

@@ -18,9 +18,9 @@ BUILD_DIR=$(get_build_dir "$BUILD_PRESET")
 
 default_binary_path() {
     if [ "$(uname -s)" = "Darwin" ]; then
-        echo "${BUILD_DIR}/bin/Ladybird.app/Contents/MacOS/"
+        echo "${BUILD_DIR}/bin/Ladybird.app/Contents/MacOS"
     else
-        echo "${BUILD_DIR}/bin/"
+        echo "${BUILD_DIR}/bin"
     fi
 }
 
@@ -31,8 +31,7 @@ WPT_CERTIFICATES=(
   "tools/certs/cacert.pem"
   "${LADYBIRD_SOURCE_DIR}/Build/ladybird/Lagom/cacert.pem"
 )
-WPT_ARGS=( "--binary=${LADYBIRD_BINARY}"
-           "--webdriver-binary=${WEBDRIVER_BINARY}"
+WPT_ARGS=( "--webdriver-binary=${WEBDRIVER_BINARY}"
            "--install-webdriver"
             "--processes=${WPT_PROCESSES}"
            "--webdriver-arg=--force-cpu-painting"
@@ -82,23 +81,39 @@ if [ "$CMD" = "--help" ] || [ "$CMD" = "help" ]; then
     exit 0
 fi
 
+set_logging_flags()
+{
+    [ -n "${1}" ] || usage;
+    [ -n "${2}" ] || usage;
+
+    log_type="${1}"
+    log_name="$(pwd -P)/${2}"
+
+    WPT_ARGS+=( "${log_type}=${log_name}" )
+}
+
 ARG=$1
-while [[ "$ARG" =~ ^--log(-(raw|unittest|xunit|html|mach|tbpl|grouped|chromium|wptreport|wptscreenshot))?$ ]]; do
+while [[ "$ARG" =~ ^(--headless|(--log(-(raw|unittest|xunit|html|mach|tbpl|grouped|chromium|wptreport|wptscreenshot))?))$ ]]; do
     case "$ARG" in
+        --headless)
+            LADYBIRD_BINARY="$(default_binary_path)/headless-browser"
+            WPT_ARGS+=( "--webdriver-arg=--headless" )
+            ;;
         --log)
-            LOG_TYPE="--log-raw"
+            set_logging_flags "--log-raw" "${2}"
+            shift
             ;;
         *)
-            LOG_TYPE="$ARG"
+            set_logging_flags "${ARG}" "${2}"
+            shift
             ;;
     esac
-    shift
-    LOG_NAME="$(pwd -P)/$1"
-    [ -n "$LOG_NAME" ] || usage;
-    WPT_ARGS+=( "${LOG_TYPE}=${LOG_NAME}" )
+
     shift
     ARG=$1
 done
+
+WPT_ARGS+=( "--binary=${LADYBIRD_BINARY}" )
 TEST_LIST=( "$@" )
 
 exit_if_running_as_root "Do not run WPT.sh as root"