1 files changed, 92 insertions, 0 deletions
diff --git a/browser/actors/PluginChild.sys.mjs b/browser/actors/PluginChild.sys.mjs
new file mode 100644
index 0000000000..6eea749ef9
--- /dev/null
+++ b/browser/actors/PluginChild.sys.mjs
@@ -0,0 +1,92 @@
+/* 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/. */
+
+// Handle GMP crashes
+export class PluginChild extends JSWindowActorChild {
+  handleEvent(event) {
+    // Ignore events for other frames.
+    let eventDoc = event.target.ownerDocument || event.target.document;
+    if (eventDoc && eventDoc != this.document) {
+      return;
+    }
+
+    let eventType = event.type;
+    if (eventType == "PluginCrashed") {
+      this.onPluginCrashed(event);
+    }
+  }
+
+  /**
+   * Determines whether or not the crashed plugin is contained within current
+   * full screen DOM element.
+   * @param fullScreenElement (DOM element)
+   *   The DOM element that is currently full screen, or null.
+   * @param domElement
+   *   The DOM element which contains the crashed plugin, or the crashed plugin
+   *   itself.
+   * @returns bool
+   *   True if the plugin is a descendant of the full screen DOM element, false otherwise.
+   **/
+  isWithinFullScreenElement(fullScreenElement, domElement) {
+    /**
+     * Traverses down iframes until it find a non-iframe full screen DOM element.
+     * @param fullScreenIframe
+     *  Target iframe to begin searching from.
+     * @returns DOM element
+     *  The full screen DOM element contained within the iframe (could be inner iframe), or the original iframe if no inner DOM element is found.
+     **/
+    let getTrueFullScreenElement = fullScreenIframe => {
+      if (
+        typeof fullScreenIframe.contentDocument !== "undefined" &&
+        fullScreenIframe.contentDocument.mozFullScreenElement
+      ) {
+        return getTrueFullScreenElement(
+          fullScreenIframe.contentDocument.mozFullScreenElement
+        );
+      }
+      return fullScreenIframe;
+    };
+
+    if (fullScreenElement.tagName === "IFRAME") {
+      fullScreenElement = getTrueFullScreenElement(fullScreenElement);
+    }
+
+    if (fullScreenElement.contains(domElement)) {
+      return true;
+    }
+    let parentIframe = domElement.ownerGlobal.frameElement;
+    if (parentIframe) {
+      return this.isWithinFullScreenElement(fullScreenElement, parentIframe);
+    }
+    return false;
+  }
+
+  /**
+   * The PluginCrashed event handler. The target of the event is the
+   * document that GMP is being used in.
+   */
+  async onPluginCrashed(aEvent) {
+    if (!this.contentWindow.PluginCrashedEvent.isInstance(aEvent)) {
+      return;
+    }
+
+    let { target, gmpPlugin, pluginID } = aEvent;
+    let fullScreenElement =
+      this.contentWindow.top.document.mozFullScreenElement;
+    if (fullScreenElement) {
+      if (this.isWithinFullScreenElement(fullScreenElement, target)) {
+        this.contentWindow.top.document.mozCancelFullScreen();
+      }
+    }
+
+    if (!gmpPlugin || !target.document) {
+      // TODO: Throw exception? How did we get here?
+      return;
+    }
+
+    this.sendAsyncMessage("PluginContent:ShowPluginCrashedNotification", {
+      pluginCrashID: { pluginID },
+    });
+  }
+}