servo: Merge #9150 - Make "mach run" use --android by default when enabled in .servobuild (from mbrubeck:run-android); r=larsbergstrom

When `.servobuild` has `android = true`, the `mach run` command should default to running on Android.

r? @larsbergstrom

Source-Repo: https://github.com/servo/servo
Source-Revision: ea4206e36259cd464480fed3ca9ac6857568bd7c

servo/python/servo/post_build_commands.py

@@ -41,7 +41,7 @@ class PostBuildCommands(CommandBase):
                      help='Run the release build')
     @CommandArgument('--dev', '-d', action='store_true',
                      help='Run the dev build')
-    @CommandArgument('--android', action='store_true',
+    @CommandArgument('--android', action='store_true', default=None,
                      help='Run on an Android device through `adb shell`')
     @CommandArgument('--debug', action='store_true',
                      help='Enable the debugger. Not specifying a '
@@ -53,10 +53,13 @@ class PostBuildCommands(CommandBase):
     @CommandArgument(
         'params', nargs='...',
         help="Command-line arguments to be passed through to Servo")
-    def run(self, params, release=False, dev=False, android=False, debug=False, debugger=None):
+    def run(self, params, release=False, dev=False, android=None, debug=False, debugger=None):
         env = self.build_env()
         env["RUST_BACKTRACE"] = "1"
 
+        if android is None:
+            android = self.config["build"]["android"]
+
         if android:
             if debug:
                 print("Android on-device debugging is not supported by mach yet. See")