Package DLLs correctly for Windows cross builds.

etc/taskcluster/decision_task.py

@@ -358,14 +358,17 @@ def android_x86_wpt():
 
 def windows_x86():
     return (
-        windows_build_task("Dev build", package=False, arch="x86")
+        windows_build_task("Dev build", arch="x86")
         .with_treeherder("Windows x86")
         .with_env(**{
             "VCVARSALL_PATH": "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\BuildTools\\VC\\Auxiliary\\Build"
         })
         .with_script(
             "python mach build --dev --target i686-pc-windows-msvc",
+            "python mach package --dev --target i686-pc-windows-msvc",
         )
+        .with_artifacts("repo/target/i686-pc-windows-msvc/debug/msi/Servo.exe",
+                        "repo/target/i686-pc-windows-msvc/debug/msi/Servo.zip")
         .find_or_create("build.windows_x86_dev." + CONFIG.task_id())
     )
 

python/servo/build_commands.py

@@ -615,7 +615,8 @@ def build(self, target=None, release=False, dev=False, jobs=None,
                     return rv
 
             if sys.platform == "win32":
-                servo_exe_dir = path.join(base_path, "debug" if dev else "release")
+                servo_exe_dir = os.path.dirname(self.get_binary_path(release, dev, target=target))
+                assert os.path.exists(servo_exe_dir)
 
                 msvc_x64 = "64" if "x86_64" in (target or host_triple()) else ""
                 # on msvc builds, use editbin to change the subsystem to windows, but only
@@ -629,6 +630,7 @@ def build(self, target=None, release=False, dev=False, jobs=None,
                                 servo_exe_dir)
                 # Search for the generated nspr4.dll
                 build_path = path.join(servo_exe_dir, "build")
+                assert os.path.exists(build_path)
 
                 def package_generated_shared_libraries(libs, build_path, servo_exe_dir):
                     for root, dirs, files in os.walk(build_path):

python/servo/command_base.py

@@ -367,7 +367,7 @@ def get_apk_path(self, release):
     def get_gstreamer_path(self):
         return path.join(self.context.topdir, "support", "linux", "gstreamer", "gst")
 
-    def get_binary_path(self, release, dev, android=False, magicleap=False):
+    def get_binary_path(self, release, dev, target=None, android=False, magicleap=False):
         # TODO(autrilla): this function could still use work - it shouldn't
         # handle quitting, or printing. It should return the path, or an error.
         base_path = self.get_target_dir()
@@ -380,6 +380,8 @@ def get_binary_path(self, release, dev, android=False, magicleap=False):
         elif android:
             base_path = path.join(base_path, "android", self.config["android"]["target"])
             binary_name = "libsimpleservo.so"
+        elif target:
+            base_path = path.join(base_path, target)
 
         release_path = path.join(base_path, "release", binary_name)
         dev_path = path.join(base_path, "debug", binary_name)

python/servo/package_commands.py

@@ -219,7 +219,7 @@ def package(self, release=False, dev=False, android=None, magicleap=None, debug=
         if magicleap:
             target = "aarch64-linux-android"
         env = self.build_env(target=target)
-        binary_path = self.get_binary_path(release, dev, android=android, magicleap=magicleap)
+        binary_path = self.get_binary_path(release, dev, target=target, android=android, magicleap=magicleap)
         dir_to_root = self.get_top_dir()
         target_dir = path.dirname(binary_path)
         if magicleap: