run_in_headless_android_emulator: add port forwarding for webdriver

etc/run_in_headless_android_emulator.py

@@ -57,6 +57,7 @@ def main(avd_name, apk_path, *args):
 
         logcat_args = ["RustAndroidGlueStdouterr:D", "*:S", "-v", "raw"]
         with terminate_on_exit(adb + ["logcat"] + logcat_args) as logcat:
+            forward_webdriver(adb, args)
             logcat.wait()
 
 
@@ -119,6 +120,28 @@ def write_args(adb, args):
         check_call(adb + ["shell", "echo %s >> %s" % (shell_quote(arg), params_file)])
 
 
+def forward_webdriver(adb, args):
+    webdriver_port = extract_arg("--webdriver", args)
+    if webdriver_port is not None:
+        wait_for_tcp_server(adb, webdriver_port)
+        port = "tcp:%s" % webdriver_port
+        check_call(adb + ["forward", port, port])
+        sys.stderr.write("Forwarding WebDriver port %s to the emulator\n" % webdriver_port)
+
+
+def extract_arg(name, args):
+    previous_arg_matches = False
+    for arg in args:
+        if previous_arg_matches:
+            return arg
+        previous_arg_matches = arg == name
+
+
+def wait_for_tcp_server(adb, port):
+    while call(adb + ["shell", "nc -z 127.0.0.1 %s" % port]) != 0:
+        time.sleep(1)
+
+
 # Copied from Python 3.3+'s shlex.quote()
 def shell_quote(arg):
     # use single quotes, and put single quotes into double quotes

tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/executors/executorservodriver.py

@@ -57,8 +57,8 @@ class ServoWebDriverProtocol(Protocol):
 
     def connect(self):
         """Connect to browser via WebDriver."""
-        # Largish timeout for the case where we're booting an Android emulator.
-        wait_for_service((self.host, self.port), timeout=120)
+        # Large timeout for the case where we're booting an Android emulator.
+        wait_for_service((self.host, self.port), timeout=300)
 
         self.session = webdriver.Session(self.host, self.port, extension=ServoCommandExtensions)
         self.session.start()