Split WPT update into its own task with a 4 hours timeout

etc/taskcluster/decision_task.py

@@ -94,6 +94,7 @@ def main(task_for):
         android_nightly("x86")
         windows_nightly()
         macos_nightly()
+        update_wpt()
 
 
 # These are disabled in a "real" decision task,
@@ -459,15 +460,33 @@ def macos_nightly():
             "./mach upload-nightly mac --secret-from-taskcluster",
         )
         .with_artifacts("repo/target/release/servo-tech-demo.dmg")
-        .with_script(
-            "./etc/ci/update-wpt-checkout fetch-and-update-expectations",
-            "./etc/ci/update-wpt-checkout open-pr",
-            "./etc/ci/update-wpt-checkout cleanup",
-        )
         .find_or_create("build.mac_x64_nightly." + CONFIG.git_sha)
     )
 
 
+def update_wpt():
+    # Reuse the release build that was made for landing the PR
+    build_task = decisionlib.Task.find("build.macos_x64_release." + CONFIG.git_sha)
+    return (
+        macos_task("WPT update")
+        .with_python2()
+        .with_treeherder("macOS x64", "WPT update")
+        .with_features("taskclusterProxy")
+        .with_scopes("secrets:get:project/servo/wpt-sync")
+        .with_index_and_artifacts_expire_in(log_artifacts_expire_in)
+        .with_max_run_time_minutes(5 * 60)
+        .with_repo()
+        .with_curl_artifact_script(build_task, "target.tar.gz")
+        .with_script("""
+            tar -xzf target.tar.gz
+            ./etc/ci/update-wpt-checkout fetch-and-update-expectations
+            ./etc/ci/update-wpt-checkout open-pr
+            ./etc/ci/update-wpt-checkout cleanup
+        """)
+        .find_or_create("wpt_update." + CONFIG.git_sha)
+    )
+
+
 def macos_wpt():
     build_task = (
         macos_build_task("Release build")