Hand browser and web app launches to the running browser directly (#13530)

* Hand browser and web app launches to the running browser directly

With a Chromium-based browser already running, each launch started a second
browser process only to pass its command line over the profile's singleton
socket and exit, ~165ms before the running browser even heard of it.
omarchy-cmd-browser-handoff sends that message itself with socat and waits
for the ACK, so a web app opens in ~210ms instead of ~430ms.

It hands off only what it can do exactly as the browser would: the packaged
browser binary rather than a wrapper, a flags file holding nothing beyond the
process flags Omarchy ships, no other data directory, and a socket we own.
Anything else, or no answer, launches the browser as before.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Hand Brave Origin launches to the running browser too

/usr/bin/brave-origin is the package's own launcher, reading
brave-origin-flags.conf, with the profile in BraveSoftware/Brave-Origin.
A web app now opens in ~158ms instead of ~345ms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

test/shell.d/browser-handoff-test.sh

@@ -0,0 +1,85 @@
+#!/bin/bash
+
+set -euo pipefail
+
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+require_command python3
+require_command socat
+
+# The handoff only stands in for the packaged browser itself.
+if [[ $(type -P chromium) != "/usr/bin/chromium" ]]; then
+  skip "browser handoff needs /usr/bin/chromium"
+  exit 0
+fi
+
+test_tmp=$(mktemp -d)
+trap 'rm -rf "$test_tmp"' EXIT
+
+export XDG_CONFIG_HOME="$test_tmp/config"
+socket="$XDG_CONFIG_HOME/chromium/SingletonSocket"
+received="$test_tmp/received"
+mkdir -p "${socket%/*}"
+flags_file="$XDG_CONFIG_HOME/chromium-flags.conf"
+cp "$ROOT/config/chromium-flags.conf" "$flags_file"
+echo "# A comment of the user's" >>"$flags_file"
+
+# A running browser's side of the singleton socket: take each command line and
+# acknowledge it, as Chromium does.
+python3 - "$socket" "$received" <<'PY' &
+import socket, sys
+server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+server.bind(sys.argv[1])
+server.listen(1)
+while True:
+    connection, _ = server.accept()
+    message = b""
+    while chunk := connection.recv(4096):
+        message += chunk
+    open(sys.argv[2], "wb").write(message)
+    connection.sendall(b"ACK")
+    connection.close()
+PY
+server=$!
+trap 'kill "$server" 2>/dev/null || true; rm -rf "$test_tmp"' EXIT
+
+for _ in $(seq 100); do
+  [[ -S $socket ]] && break
+  sleep 0.02
+done
+
+(cd "$test_tmp" && "$ROOT/bin/omarchy-cmd-browser-handoff" chromium --app="https://example.test/a b") ||
+  fail "the running browser acknowledges a handed off command line"
+
+expected=$(printf 'START\0%s\0browser\0--app=https://example.test/a b' "$test_tmp" | od -c)
+[[ $(od -c <"$received") == "$expected" ]] ||
+  fail "the handoff sends the working directory and arguments as Chromium's singleton expects" "$(od -c <"$received")"
+pass "a command line is handed to the running browser over its singleton socket"
+
+! "$ROOT/bin/omarchy-cmd-browser-handoff" chromium --user-data-dir=/elsewhere https://example.test ||
+  fail "another data directory is left to a browser of its own"
+mkdir -p "$test_tmp/wrapper"
+printf '#!/bin/bash\nexec /usr/bin/chromium --profile-directory=Work "$@"\n' >"$test_tmp/wrapper/chromium"
+chmod +x "$test_tmp/wrapper/chromium"
+! PATH="$test_tmp/wrapper:$PATH" "$ROOT/bin/omarchy-cmd-browser-handoff" chromium https://example.test ||
+  fail "a wrapper standing in for the browser is left to run"
+! CHROME_USER_DATA_DIR=/elsewhere "$ROOT/bin/omarchy-cmd-browser-handoff" chromium https://example.test ||
+  fail "a data directory from the environment is left to a browser of its own"
+
+# The handoff forwards no flags file, so any flag beyond Omarchy's own, which
+# may be meant for each launch, needs the launcher.
+for flag in '--new-window' '--enable-features=A --profile-directory="Profile 1"'; do
+  cp "$ROOT/config/chromium-flags.conf" "$flags_file"
+  echo "$flag" >>"$flags_file"
+  ! "$ROOT/bin/omarchy-cmd-browser-handoff" chromium https://example.test ||
+    fail "a flags file with $flag is left to the launcher"
+done
+
+# The browser is gone but its socket file is left, as after a crash.
+kill "$server"
+wait "$server" 2>/dev/null || true
+! "$ROOT/bin/omarchy-cmd-browser-handoff" chromium --app=https://example.test ||
+  fail "a socket no browser answers on fails the handoff"
+! "$ROOT/bin/omarchy-cmd-browser-handoff" firefox https://example.test ||
+  fail "a browser without a singleton socket fails the handoff"
+pass "the handoff fails when no Chromium-based browser answers, so the caller launches one"

test/shell.d/launch-browser-test.sh

@@ -10,6 +10,9 @@ trap 'rm -rf "$test_tmp"' EXIT
 mock_bin="$test_tmp/bin"
 test_home="$test_tmp/home"
 mkdir -p "$mock_bin" "$test_home/.local/share/applications"
+# Keep the launcher away from the running browser's singleton socket, which it
+# would otherwise hand these test URLs to.
+export XDG_CONFIG_HOME="$test_home/.config" XDG_DATA_HOME="$test_home/.local/share"
 
 cat >"$test_home/.local/share/applications/chromium.desktop" <<'EOF'
 [Desktop Entry]
@@ -79,3 +82,16 @@ grep -Fx '^chromium.*$' "$focus_log" >/dev/null ||
   fail "browser launcher focuses the browser resolved from the HTTPS handler"
 
 pass "browser launcher follows opened links to the browser workspace"
+
+rm -f "$launch_log"
+cat >"$mock_bin/omarchy-cmd-browser-handoff" <<'SH'
+#!/bin/bash
+[[ $1 == "chromium" && $2 == "https://example.test/running" ]]
+SH
+chmod +x "$mock_bin/omarchy-cmd-browser-handoff"
+
+HOME="$test_home" PATH="$mock_bin:$PATH" OMARCHY_TEST_BROWSER_LAUNCH="$launch_log" \
+  OMARCHY_TEST_BROWSER_FOCUS="$focus_log" bash "$ROOT/bin/omarchy-launch-browser" "https://example.test/running"
+
+[[ ! -e $launch_log ]] || fail "browser launcher starts no browser when the running one takes the URL"
+pass "browser launcher hands a URL to the running browser"