1 files changed, 50 insertions, 0 deletions
diff --git a/toolkit/content/browser-child.js b/toolkit/content/browser-child.js
new file mode 100644
index 0000000000..7f9620fc19
--- /dev/null
+++ b/toolkit/content/browser-child.js
@@ -0,0 +1,50 @@
+/* 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/. */
+
+/* eslint-env mozilla/frame-script */
+
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+ChromeUtils.defineModuleGetter(
+  this,
+  "BrowserUtils",
+  "resource://gre/modules/BrowserUtils.jsm"
+);
+
+try {
+  docShell
+    .QueryInterface(Ci.nsIInterfaceRequestor)
+    .getInterface(Ci.nsIBrowserChild)
+    .beginSendingWebProgressEventsToParent();
+} catch (e) {
+  // In responsive design mode, we do not have a BrowserChild for the in-parent
+  // document.
+}
+
+// This message is used to measure content process startup performance in Talos
+// tests.
+sendAsyncMessage("Content:BrowserChildReady", {
+  time: Services.telemetry.msSystemNow(),
+});
+
+// This is here for now until we find a better way of forcing an about:blank load
+// with a particular principal that doesn't involve the message manager. We can't
+// do this with JS Window Actors for now because JS Window Actors are tied to the
+// document principals themselves, so forcing the load with a new principal is
+// self-destructive in that case.
+addMessageListener("BrowserElement:CreateAboutBlank", message => {
+  if (!content.document || content.document.documentURI != "about:blank") {
+    throw new Error("Can't create a content viewer unless on about:blank");
+  }
+  let { principal, partitionedPrincipal } = message.data;
+  principal = BrowserUtils.principalWithMatchingOA(
+    principal,
+    content.document.nodePrincipal
+  );
+  partitionedPrincipal = BrowserUtils.principalWithMatchingOA(
+    partitionedPrincipal,
+    content.document.partitionedPrincipal
+  );
+  docShell.createAboutBlankContentViewer(principal, partitionedPrincipal);
+});