1 files changed, 61 insertions, 0 deletions
diff --git a/testing/mochitest/ShutdownLeaksCollector.sys.mjs b/testing/mochitest/ShutdownLeaksCollector.sys.mjs
new file mode 100644
index 0000000000..44b2025429
--- /dev/null
+++ b/testing/mochitest/ShutdownLeaksCollector.sys.mjs
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { setTimeout } from "resource://gre/modules/Timer.sys.mjs";
+
+// This listens for the message "browser-test:collect-request". When it gets it,
+// it runs some GCs and CCs, then prints out a message indicating the collections
+// are complete. Mochitest uses this information to determine when windows and
+// docshells should be destroyed.
+
+export var ContentCollector = {
+  init() {
+    let processType = Services.appinfo.processType;
+    if (processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT) {
+      // In the main process, we handle triggering collections in browser-test.js
+      return;
+    }
+
+    Services.cpmm.addMessageListener("browser-test:collect-request", this);
+  },
+
+  receiveMessage(aMessage) {
+    switch (aMessage.name) {
+      case "browser-test:collect-request":
+        Services.obs.notifyObservers(null, "memory-pressure", "heap-minimize");
+
+        Cu.forceGC();
+        Cu.forceCC();
+
+        let shutdownCleanup = aCallback => {
+          Cu.schedulePreciseShrinkingGC(() => {
+            // Run the GC and CC a few times to make sure that as much
+            // as possible is freed.
+            Cu.forceGC();
+            Cu.forceCC();
+            aCallback();
+          });
+        };
+
+        shutdownCleanup(() => {
+          setTimeout(() => {
+            shutdownCleanup(() => {
+              this.finish();
+            });
+          }, 1000);
+        });
+
+        break;
+    }
+  },
+
+  finish() {
+    let pid = Services.appinfo.processID;
+    dump("Completed ShutdownLeaks collections in process " + pid + "\n");
+
+    Services.cpmm.removeMessageListener("browser-test:collect-request", this);
+  },
+};
+
+ContentCollector.init();