Auto merge of #21213 - servo:android-wpt, r=nox+jgraham

Add some support for WPT tests in an Android emulator through WebDriver

This succeeds on my machine:

`./mach test-wpt --product servodriver --binary etc/run_in_headless_android_emulator.py --binary-arg servo-x86 --binary-arg target/i686-linux-android/release/servo.apk /_mozilla/mozilla/DOMParser.html`

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tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/servodriver.py

@@ -37,7 +37,9 @@ def check_args(**kwargs):
 def browser_kwargs(test_type, run_info_data, **kwargs):
     return {
         "binary": kwargs["binary"],
+        "binary_args": kwargs["binary_args"],
         "debug_info": kwargs["debug_info"],
+        "server_config": kwargs["config"],
         "user_stylesheets": kwargs.get("user_stylesheets"),
     }
 
@@ -71,16 +73,19 @@ def write_hosts_file(config):
 
 class ServoWebDriverBrowser(Browser):
     used_ports = set()
+    init_timeout = 300  # Large timeout for cases where we're booting an Android emulator
 
     def __init__(self, logger, binary, debug_info=None, webdriver_host="127.0.0.1",
-                 user_stylesheets=None):
+                 server_config=None, binary_args=None, user_stylesheets=None):
         Browser.__init__(self, logger)
         self.binary = binary
+        self.binary_args = binary_args or []
         self.webdriver_host = webdriver_host
         self.webdriver_port = None
         self.proc = None
         self.debug_info = debug_info
-        self.hosts_path = write_hosts_file()
+        self.hosts_path = write_hosts_file(server_config)
+        self.server_ports = server_config.ports if server_config else {}
         self.command = None
         self.user_stylesheets = user_stylesheets if user_stylesheets else []
 
@@ -91,10 +96,16 @@ class ServoWebDriverBrowser(Browser):
         env = os.environ.copy()
         env["HOST_FILE"] = self.hosts_path
         env["RUST_BACKTRACE"] = "1"
+        env["EMULATOR_REVERSE_FORWARD_PORTS"] = ",".join(
+            str(port)
+            for _protocol, ports in self.server_ports.items()
+            for port in ports
+            if port
+        )
 
         debug_args, command = browser_command(
             self.binary,
-            [
+            self.binary_args + [
                 "--hard-fail",
                 "--webdriver", str(self.webdriver_port),
                 "about:blank",
@@ -151,9 +162,10 @@ class ServoWebDriverBrowser(Browser):
 
     def cleanup(self):
         self.stop()
-        shutil.rmtree(os.path.dirname(self.hosts_file))
+        os.remove(self.hosts_path)
 
     def executor_browser(self):
         assert self.webdriver_port is not None
         return ExecutorBrowser, {"webdriver_host": self.webdriver_host,
-                                 "webdriver_port": self.webdriver_port}
+                                 "webdriver_port": self.webdriver_port,
+                                 "init_timeout": self.init_timeout}

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

@@ -6,13 +6,16 @@ import time
 import traceback
 
 from .base import (Protocol,
+                   BaseProtocolPart,
                    RefTestExecutor,
                    RefTestImplementation,
                    TestharnessExecutor,
                    strip_server)
 from ..testrunner import Stop
+from ..webdriver_server import wait_for_service
 
 webdriver = None
+ServoCommandExtensions = None
 
 here = os.path.join(os.path.split(__file__)[0])
 
@@ -23,20 +26,76 @@ def do_delayed_imports():
     global webdriver
     import webdriver
 
+    global ServoCommandExtensions
+    class ServoCommandExtensions(object):
+        def __init__(self, session):
+            self.session = session
+
+        @webdriver.client.command
+        def get_prefs(self, *prefs):
+            body = {"prefs": list(prefs)}
+            return self.session.send_session_command("POST", "servo/prefs/get", body)
+
+        @webdriver.client.command
+        def set_prefs(self, prefs):
+            body = {"prefs": prefs}
+            return self.session.send_session_command("POST", "servo/prefs/set", body)
+
+        @webdriver.client.command
+        def reset_prefs(self, *prefs):
+            body = {"prefs": list(prefs)}
+            return self.session.send_session_command("POST", "servo/prefs/reset", body)
+
+        def change_prefs(self, old_prefs, new_prefs):
+            # Servo interprets reset with an empty list as reset everything
+            if old_prefs:
+                self.reset_prefs(*old_prefs.keys())
+            self.set_prefs({k: parse_pref_value(v) for k, v in new_prefs.items()})
+
+
+# See parse_pref_from_command_line() in components/config/opts.rs
+def parse_pref_value(value):
+    if value == "true":
+        return True
+    if value == "false":
+        return False
+    try:
+        return float(value)
+    except ValueError:
+        return value
+
+
+class ServoBaseProtocolPart(BaseProtocolPart):
+    def execute_script(self, script, async=False):
+        pass
+
+    def set_timeout(self, timeout):
+        pass
+
+    def wait(self):
+        pass
+
+    def set_window(self, handle):
+        pass
+
 
 class ServoWebDriverProtocol(Protocol):
+    implements = [ServoBaseProtocolPart]
+
     def __init__(self, executor, browser, capabilities, **kwargs):
         do_delayed_imports()
         Protocol.__init__(self, executor, browser)
         self.capabilities = capabilities
         self.host = browser.webdriver_host
         self.port = browser.webdriver_port
+        self.init_timeout = browser.init_timeout
         self.session = None
 
     def connect(self):
         """Connect to browser via WebDriver."""
-        self.session = webdriver.Session(self.host, self.port,
-                                         extension=webdriver.servo.ServoCommandExtensions)
+        wait_for_service((self.host, self.port), timeout=self.init_timeout)
+
+        self.session = webdriver.Session(self.host, self.port, extension=ServoCommandExtensions)
         self.session.start()
 
     def after_connect(self):
@@ -70,11 +129,6 @@ class ServoWebDriverProtocol(Protocol):
                 self.logger.error(traceback.format_exc(e))
                 break
 
-    def on_environment_change(self, old_environment, new_environment):
-        #Unset all the old prefs
-        self.session.extension.reset_prefs(*old_environment.get("prefs", {}).keys())
-        self.session.extension.set_prefs(new_environment.get("prefs", {}))
-
 
 class ServoWebDriverRun(object):
     def __init__(self, func, session, url, timeout, current_timeout=None):
@@ -174,6 +228,12 @@ class ServoWebDriverTestharnessExecutor(TestharnessExecutor):
         session.back()
         return result
 
+    def on_environment_change(self, new_environment):
+        self.protocol.session.extension.change_prefs(
+            self.last_environment.get("prefs", {}),
+            new_environment.get("prefs", {})
+        )
+
 
 class TimeoutError(Exception):
     pass
@@ -240,3 +300,9 @@ class ServoWebDriverRefTestExecutor(RefTestExecutor):
         session.url = url
         session.execute_async_script(self.wait_script)
         return session.screenshot()
+
+    def on_environment_change(self, new_environment):
+        self.protocol.session.extension.change_prefs(
+            self.last_environment.get("prefs", {}),
+            new_environment.get("prefs", {})
+        )