1 files changed, 98 insertions, 0 deletions
diff --git a/comm/mail/modules/MailE10SUtils.jsm b/comm/mail/modules/MailE10SUtils.jsm
new file mode 100644
index 0000000000..224dd50a71
--- /dev/null
+++ b/comm/mail/modules/MailE10SUtils.jsm
@@ -0,0 +1,98 @@
+/* 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/. */
+
+const EXPORTED_SYMBOLS = ["MailE10SUtils"];
+
+const { E10SUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/E10SUtils.sys.mjs"
+);
+const { ExtensionParent } = ChromeUtils.importESModule(
+  "resource://gre/modules/ExtensionParent.sys.mjs"
+);
+
+var MailE10SUtils = {
+  /**
+   * Loads about:blank in `browser` without switching remoteness. about:blank
+   * can load in a local browser or a remote browser, and `loadURI` will make
+   * it load in a remote browser even if you don't want it to.
+   *
+   * @param {nsIBrowser} browser
+   */
+  loadAboutBlank(browser) {
+    if (!browser.currentURI || browser.currentURI.spec == "about:blank") {
+      return;
+    }
+    browser.loadURI(Services.io.newURI("about:blank"), {
+      triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
+      remoteTypeOverride: browser.remoteType,
+    });
+  },
+
+  /**
+   * Loads `uri` in `browser`, changing to a remote/local browser if necessary.
+   *
+   * @see `nsIWebNavigation.loadURI`
+   *
+   * @param {nsIBrowser} browser
+   * @param {string} uri
+   * @param {object} params
+   */
+  loadURI(browser, uri, params = {}) {
+    let multiProcess = browser.ownerGlobal.docShell.QueryInterface(
+      Ci.nsILoadContext
+    ).useRemoteTabs;
+    let remoteSubframes = browser.ownerGlobal.docShell.QueryInterface(
+      Ci.nsILoadContext
+    ).useRemoteSubframes;
+
+    let isRemote = browser.getAttribute("remote") == "true";
+    let remoteType = E10SUtils.getRemoteTypeForURI(
+      uri,
+      multiProcess,
+      remoteSubframes
+    );
+    let shouldBeRemote = remoteType !== E10SUtils.NOT_REMOTE;
+
+    if (shouldBeRemote != isRemote) {
+      this.changeRemoteness(browser, remoteType);
+    }
+
+    params.triggeringPrincipal =
+      params.triggeringPrincipal ||
+      Services.scriptSecurityManager.getSystemPrincipal();
+    browser.fixupAndLoadURIString(uri, params);
+  },
+
+  /**
+   * Force `browser` to be a remote/local browser.
+   *
+   * @see E10SUtils.jsm for remote types.
+   *
+   * @param {nsIBrowser} browser - the browser to enforce the remoteness of.
+   * @param {string} remoteType - the remoteness to enforce.
+   * @returns {boolean} true if any change happened on the browser (which would
+   *    not be the case if its remoteness is already in the correct state).
+   */
+  changeRemoteness(browser, remoteType) {
+    if (browser.remoteType == remoteType) {
+      return false;
+    }
+
+    browser.destroy();
+
+    if (remoteType) {
+      browser.setAttribute("remote", "true");
+      browser.setAttribute("remoteType", remoteType);
+    } else {
+      browser.setAttribute("remote", "false");
+      browser.removeAttribute("remoteType");
+    }
+
+    browser.changeRemoteness({ remoteType });
+    browser.construct();
+    ExtensionParent.apiManager.emit("extension-browser-inserted", browser);
+
+    return true;
+  },
+};