Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

25 files changed, 4967 insertions, 0 deletions

diff --git a/toolkit/modules/tests/browser/browser.ini b/toolkit/modules/tests/browser/browser.ini
new file mode 100644
index 0000000000..e9a77185da
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser.ini
@@ -0,0 +1,37 @@
+[DEFAULT]
+support-files =
+  file_FinderIframeTest.html
+  file_FinderSample.html
+  file_getSelectionDetails_inputs.html
+  head.js
+
+[browser_AsyncPrefs.js]
+[browser_BrowserUtils.js]
+[browser_CreditCard.js]
+skip-if = apple_silicon # Disabled due to bleedover with other tests when run in regular suites; passes in "failures" jobs
+[browser_Deprecated.js]
+[browser_Finder.js]
+[browser_Finder_hidden_textarea.js]
+skip-if = verify && debug
+[browser_Finder_offscreen_text.js]
+[browser_Finder_overflowed_onscreen.js]
+[browser_Finder_overflowed_textarea.js]
+skip-if = verify && debug && (os == 'mac' || os == 'linux')
+[browser_Finder_pointer_events_none.js]
+[browser_Finder_skip_invisible_and_option.js]
+[browser_Finder_vertical_text.js]
+[browser_FinderHighlighter.js]
+skip-if = true # bug 1831518 covers re-enabling
+# skip-if = debug || os == "linux"
+[browser_FinderHighlighter2.js]
+skip-if = true # bug 1831518 covers re-enabling
+# skip-if = debug || os == "linux"
+[browser_Geometry.js]
+[browser_InlineSpellChecker.js]
+[browser_Troubleshoot.js]
+skip-if = os == "win" && os_version == "6.1" # bug 1715857
+[browser_web_channel.js]
+https_first_disabled = true
+support-files =
+  file_web_channel.html
+  file_web_channel_iframe.html
diff --git a/toolkit/modules/tests/browser/browser_AsyncPrefs.js b/toolkit/modules/tests/browser/browser_AsyncPrefs.js
new file mode 100644
index 0000000000..96eadc4b2e
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_AsyncPrefs.js
@@ -0,0 +1,133 @@
+"use strict";
+
+const kWhiteListedBool = "testing.allowed-prefs.some-bool-pref";
+const kWhiteListedChar = "testing.allowed-prefs.some-char-pref";
+const kWhiteListedInt = "testing.allowed-prefs.some-int-pref";
+
+function resetPrefs() {
+  for (let pref of [kWhiteListedBool, kWhiteListedChar, kWhiteListedBool]) {
+    Services.prefs.clearUserPref(pref);
+  }
+}
+
+registerCleanupFunction(resetPrefs);
+
+Services.prefs
+  .getDefaultBranch("testing.allowed-prefs.")
+  .setBoolPref("some-bool-pref", false);
+Services.prefs
+  .getDefaultBranch("testing.allowed-prefs.")
+  .setCharPref("some-char-pref", "");
+Services.prefs
+  .getDefaultBranch("testing.allowed-prefs.")
+  .setIntPref("some-int-pref", 0);
+
+async function runTest() {
+  let { AsyncPrefs } = ChromeUtils.importESModule(
+    "resource://gre/modules/AsyncPrefs.sys.mjs"
+  );
+  const kInChildProcess =
+    Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_CONTENT;
+
+  // Need to define these again because when run in a content task we have no scope access.
+  const kNotWhiteListed = "some.pref.thats.not.whitelisted";
+  const kWhiteListedBool = "testing.allowed-prefs.some-bool-pref";
+  const kWhiteListedChar = "testing.allowed-prefs.some-char-pref";
+  const kWhiteListedInt = "testing.allowed-prefs.some-int-pref";
+
+  const procDesc = kInChildProcess ? "child process" : "parent process";
+
+  const valueResultMap = [
+    [true, "Bool"],
+    [false, "Bool"],
+    [10, "Int"],
+    [-1, "Int"],
+    ["", "Char"],
+    ["stuff", "Char"],
+    [[], false],
+    [{}, false],
+    [Services.io.newURI("http://mozilla.org/"), false],
+  ];
+
+  const prefMap = [
+    ["Bool", kWhiteListedBool],
+    ["Char", kWhiteListedChar],
+    ["Int", kWhiteListedInt],
+  ];
+
+  function doesFail(pref, value) {
+    let msg = `Should not succeed setting ${pref} to ${value} in ${procDesc}`;
+    return AsyncPrefs.set(pref, value).then(
+      () => ok(false, msg),
+      error => ok(true, msg + "; " + error)
+    );
+  }
+
+  function doesWork(pref, value) {
+    let msg = `Should be able to set ${pref} to ${value} in ${procDesc}`;
+    return AsyncPrefs.set(pref, value).then(
+      () => ok(true, msg),
+      error => ok(false, msg + "; " + error)
+    );
+  }
+
+  function doReset(pref) {
+    let msg = `Should be able to reset ${pref} in ${procDesc}`;
+    return AsyncPrefs.reset(pref).then(
+      () => ok(true, msg),
+      () => ok(false, msg)
+    );
+  }
+
+  for (let [val] of valueResultMap) {
+    await doesFail(kNotWhiteListed, val);
+    is(
+      Services.prefs.prefHasUserValue(kNotWhiteListed),
+      false,
+      "Pref shouldn't get changed"
+    );
+  }
+
+  let resetMsg = `Should not succeed resetting ${kNotWhiteListed} in ${procDesc}`;
+  AsyncPrefs.reset(kNotWhiteListed).then(
+    () => ok(false, resetMsg),
+    error => ok(true, resetMsg + "; " + error)
+  );
+
+  for (let [type, pref] of prefMap) {
+    for (let [val, result] of valueResultMap) {
+      if (result == type) {
+        await doesWork(pref, val);
+        is(
+          Services.prefs["get" + type + "Pref"](pref),
+          val,
+          "Pref should have been updated"
+        );
+        await doReset(pref);
+      } else {
+        await doesFail(pref, val);
+        is(
+          Services.prefs.prefHasUserValue(pref),
+          false,
+          `Pref ${pref} shouldn't get changed`
+        );
+      }
+    }
+  }
+}
+
+add_task(async function runInParent() {
+  await runTest();
+  resetPrefs();
+});
+
+if (gMultiProcessBrowser) {
+  add_task(async function runInChild() {
+    ok(
+      gBrowser.selectedBrowser.isRemoteBrowser,
+      "Should actually run this in child process"
+    );
+    await SpecialPowers.spawn(gBrowser.selectedBrowser, [], runTest);
+    resetPrefs();
+  });
+}
diff --git a/toolkit/modules/tests/browser/browser_BrowserUtils.js b/toolkit/modules/tests/browser/browser_BrowserUtils.js
new file mode 100644
index 0000000000..da28c07b69
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_BrowserUtils.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/. */
+
+add_task(async function test_getSelectionDetails_input() {
+  // Mostly a regression test for bug 1420560
+  const url = kFixtureBaseURL + "file_getSelectionDetails_inputs.html";
+  await BrowserTestUtils.withNewTab({ gBrowser, url }, async browser => {
+    await SpecialPowers.spawn(browser, [], () => {
+      function checkSelection({ id, text, linkURL }) {
+        const { SelectionUtils } = ChromeUtils.importESModule(
+          "resource://gre/modules/SelectionUtils.sys.mjs"
+        );
+        content.document.getElementById(id).select();
+        // It seems that when running as a test, the previous line will set
+        // the both the window's selection and the input's selection to contain
+        // the input's text. Outside of tests, only the input's selection seems
+        // to be updated, so we explicitly clear the window's selection to
+        // ensure we're doing the right thing in the case that only the input's
+        // selection is present.
+        content.getSelection().removeAllRanges();
+        let info = SelectionUtils.getSelectionDetails(content);
+        Assert.equal(text, info.text);
+        Assert.ok(!info.collapsed);
+        Assert.equal(linkURL, info.linkURL);
+      }
+
+      checkSelection({
+        id: "url-no-scheme",
+        text: "test.example.com",
+        linkURL: "http://test.example.com/",
+      });
+      checkSelection({
+        id: "url-with-scheme",
+        text: "https://test.example.com",
+        linkURL: "https://test.example.com/",
+      });
+      checkSelection({
+        id: "not-url",
+        text: "foo. bar",
+        linkURL: null,
+      });
+      checkSelection({
+        id: "not-url-number",
+        text: "3.5",
+        linkURL: null,
+      });
+    });
+  });
+});
diff --git a/toolkit/modules/tests/browser/browser_CreditCard.js b/toolkit/modules/tests/browser/browser_CreditCard.js
new file mode 100644
index 0000000000..304c988707
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_CreditCard.js
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { CreditCard } = ChromeUtils.importESModule(
+  "resource://gre/modules/CreditCard.sys.mjs"
+);
+const { OSKeyStore } = ChromeUtils.importESModule(
+  "resource://gre/modules/OSKeyStore.sys.mjs"
+);
+const { OSKeyStoreTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/OSKeyStoreTestUtils.sys.mjs"
+);
+
+let oldGetters = {};
+let gFakeLoggedIn = true;
+
+add_setup(function () {
+  OSKeyStoreTestUtils.setup();
+  oldGetters.isLoggedIn = Object.getOwnPropertyDescriptor(
+    OSKeyStore,
+    "isLoggedIn"
+  ).get;
+  OSKeyStore.__defineGetter__("isLoggedIn", () => gFakeLoggedIn);
+  registerCleanupFunction(async () => {
+    OSKeyStore.__defineGetter__("isLoggedIn", oldGetters.isLoggedIn);
+    await OSKeyStoreTestUtils.cleanup();
+  });
+});
+
+add_task(async function test_getLabel_withOSKeyStore() {
+  ok(
+    OSKeyStore.isLoggedIn,
+    "Confirm that OSKeyStore is faked and thinks it is logged in"
+  );
+
+  const ccNumber = "4111111111111111";
+  const encryptedNumber = await OSKeyStore.encrypt(ccNumber);
+  const decryptedNumber = await OSKeyStore.decrypt(encryptedNumber);
+  is(decryptedNumber, ccNumber, "Decrypted CC number should match original");
+
+  const name = "Foxkeh";
+  const label = CreditCard.getLabel({ name: "Foxkeh", number: ccNumber });
+  is(label, `**** 1111, ${name}`, "Label matches");
+});
diff --git a/toolkit/modules/tests/browser/browser_Deprecated.js b/toolkit/modules/tests/browser/browser_Deprecated.js
new file mode 100644
index 0000000000..94396b1384
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Deprecated.js
@@ -0,0 +1,131 @@
+/* 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 PREF_DEPRECATION_WARNINGS = "devtools.errorconsole.deprecation_warnings";
+
+// Using this named functions to test deprecation and the properly logged
+// callstacks.
+function basicDeprecatedFunction() {
+  Deprecated.warning("this method is deprecated.", "https://example.com");
+  return true;
+}
+
+function deprecationFunctionBogusCallstack() {
+  Deprecated.warning("this method is deprecated.", "https://example.com", {
+    caller: {},
+  });
+  return true;
+}
+
+function deprecationFunctionCustomCallstack() {
+  // Get the nsIStackFrame that will contain the name of this function.
+  function getStack() {
+    return Components.stack;
+  }
+  Deprecated.warning(
+    "this method is deprecated.",
+    "https://example.com",
+    getStack()
+  );
+  return true;
+}
+
+var tests = [
+  // Test deprecation warning without passing the callstack.
+  {
+    deprecatedFunction: basicDeprecatedFunction,
+    expectedObservation(aMessage) {
+      testAMessage(aMessage);
+      ok(
+        aMessage.indexOf("basicDeprecatedFunction") > 0,
+        "Callstack is correctly logged."
+      );
+    },
+  },
+  // Test a reported error when URL to documentation is not passed.
+  {
+    deprecatedFunction() {
+      Deprecated.warning("this method is deprecated.");
+      return true;
+    },
+    expectedObservation(aMessage) {
+      ok(
+        aMessage.indexOf("must provide a URL") > 0,
+        "Deprecation warning logged an empty URL argument."
+      );
+    },
+  },
+  // Test deprecation with a bogus callstack passed as an argument (it will be
+  // replaced with the current call stack).
+  {
+    deprecatedFunction: deprecationFunctionBogusCallstack,
+    expectedObservation(aMessage) {
+      testAMessage(aMessage);
+      ok(
+        aMessage.indexOf("deprecationFunctionBogusCallstack") > 0,
+        "Callstack is correctly logged."
+      );
+    },
+  },
+  // Test deprecation with a valid custom callstack passed as an argument.
+  {
+    deprecatedFunction: deprecationFunctionCustomCallstack,
+    expectedObservation(aMessage) {
+      testAMessage(aMessage);
+      ok(
+        aMessage.indexOf("deprecationFunctionCustomCallstack") > 0,
+        "Callstack is correctly logged."
+      );
+    },
+    // Set pref to true.
+    logWarnings: true,
+  },
+];
+
+// Test Console Message attributes.
+function testAMessage(aMessage) {
+  ok(
+    aMessage.indexOf("DEPRECATION WARNING: this method is deprecated.") === 0,
+    "Deprecation is correctly logged."
+  );
+  ok(aMessage.indexOf("https://example.com") > 0, "URL is correctly logged.");
+}
+
+add_task(async function test_setup() {
+  Services.prefs.setBoolPref(PREF_DEPRECATION_WARNINGS, true);
+
+  // Check if Deprecated is loaded.
+  ok(Deprecated, "Deprecated object exists");
+});
+
+add_task(async function test_pref_enabled() {
+  for (let [idx, test] of tests.entries()) {
+    info("Running test #" + idx);
+
+    let promiseObserved = TestUtils.consoleMessageObserved(subject => {
+      let msg = subject.wrappedJSObject.arguments?.[0];
+      return (
+        msg.includes("DEPRECATION WARNING: ") ||
+        msg.includes("must provide a URL")
+      );
+    });
+
+    test.deprecatedFunction();
+
+    let msg = await promiseObserved;
+
+    test.expectedObservation(msg.wrappedJSObject.arguments?.[0]);
+  }
+});
+
+add_task(async function test_pref_disabled() {
+  // Deprecation warnings will be logged only when the preference is set.
+  Services.prefs.setBoolPref(PREF_DEPRECATION_WARNINGS, false);
+
+  let endFn = TestUtils.listenForConsoleMessages();
+  basicDeprecatedFunction();
+
+  let messages = await endFn();
+  Assert.equal(messages.length, 0, "Should not have received any messages");
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder.js b/toolkit/modules/tests/browser/browser_Finder.js
new file mode 100644
index 0000000000..7bcf7e8a00
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder.js
@@ -0,0 +1,73 @@
+/* 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/. */
+
+add_task(async function () {
+  const url =
+    "data:text/html;base64," +
+    btoa(
+      '<body><iframe srcdoc="content"/></iframe>' +
+        '<a href="http://test.com">test link</a>'
+    );
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, url);
+
+  let finder = tab.linkedBrowser.finder;
+  let listener = {
+    onFindResult() {
+      ok(false, "onFindResult callback wasn't replaced");
+    },
+    onHighlightFinished() {
+      ok(false, "onHighlightFinished callback wasn't replaced");
+    },
+  };
+  finder.addResultListener(listener);
+
+  function waitForFind(which = "onFindResult") {
+    return new Promise(resolve => {
+      listener[which] = resolve;
+    });
+  }
+
+  let promiseFind = waitForFind("onHighlightFinished");
+  finder.highlight(true, "content");
+  let findResult = await promiseFind;
+  Assert.ok(findResult.found, "should find string");
+
+  promiseFind = waitForFind("onHighlightFinished");
+  finder.highlight(true, "Bla");
+  findResult = await promiseFind;
+  Assert.ok(!findResult.found, "should not find string");
+
+  // Search only for links and draw outlines.
+  promiseFind = waitForFind();
+  finder.fastFind("test link", true, true);
+  findResult = await promiseFind;
+  is(findResult.result, Ci.nsITypeAheadFind.FIND_FOUND, "should find link");
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async function (arg) {
+    Assert.ok(
+      !!content.document.getElementsByTagName("a")[0].style.outline,
+      "outline set"
+    );
+  });
+
+  // Just a simple search for "test link".
+  promiseFind = waitForFind();
+  finder.fastFind("test link", false, false);
+  findResult = await promiseFind;
+  is(
+    findResult.result,
+    Ci.nsITypeAheadFind.FIND_FOUND,
+    "should find link again"
+  );
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async function (arg) {
+    Assert.ok(
+      !content.document.getElementsByTagName("a")[0].style.outline,
+      "outline not set"
+    );
+  });
+
+  finder.removeResultListener(listener);
+  gBrowser.removeTab(tab);
+});
diff --git a/toolkit/modules/tests/browser/browser_FinderHighlighter.js b/toolkit/modules/tests/browser/browser_FinderHighlighter.js
new file mode 100644
index 0000000000..cc09888206
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_FinderHighlighter.js
@@ -0,0 +1,415 @@
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+"use strict";
+
+const kIteratorTimeout = Services.prefs.getIntPref("findbar.iteratorTimeout");
+const kPrefHighlightAll = "findbar.highlightAll";
+const kPrefModalHighlight = "findbar.modalHighlight";
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      [kPrefHighlightAll, true],
+      [kPrefModalHighlight, true],
+    ],
+  });
+});
+
+// Test the results of modal highlighting, which is on by default.
+add_task(async function testModalResults() {
+  let tests = new Map([
+    [
+      "Roland",
+      {
+        rectCount: 2,
+        insertCalls: [2, 4],
+        removeCalls: [0, 1],
+        animationCalls: [1, 2],
+      },
+    ],
+    [
+      "their law might propagate their kind",
+      {
+        rectCount: 2,
+        insertCalls: [5, 6],
+        removeCalls: [4, 5],
+        // eslint-disable-next-line object-shorthand
+        extraTest: function (maskNode, outlineNode, rects) {
+          Assert.equal(
+            outlineNode.getElementsByTagName("div").length,
+            2,
+            "There should be multiple rects drawn"
+          );
+        },
+      },
+    ],
+    [
+      "ro",
+      {
+        rectCount: 41,
+        insertCalls: [1, 4],
+        removeCalls: [0, 2],
+      },
+    ],
+    [
+      "new",
+      {
+        rectCount: 2,
+        insertCalls: [1, 4],
+        removeCalls: [0, 2],
+      },
+    ],
+    [
+      "o",
+      {
+        rectCount: 492,
+        insertCalls: [1, 4],
+        removeCalls: [0, 2],
+      },
+    ],
+  ]);
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    for (let [word, expectedResult] of tests) {
+      await promiseOpenFindbar(findbar);
+      Assert.ok(!findbar.hidden, "Findbar should be open now.");
+
+      let timeout = kIteratorTimeout;
+      if (word.length == 1) {
+        timeout *= 4;
+      } else if (word.length == 2) {
+        timeout *= 2;
+      }
+      await new Promise(resolve => setTimeout(resolve, timeout));
+      let promise = promiseTestHighlighterOutput(
+        browser,
+        word,
+        expectedResult,
+        expectedResult.extraTest
+      );
+      await promiseEnterStringIntoFindField(findbar, word);
+      await promise;
+
+      findbar.close(true);
+    }
+  });
+});
+
+// Test if runtime switching of highlight modes between modal and non-modal works
+// as expected.
+add_task(async function testModalSwitching() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    await promiseOpenFindbar(findbar);
+    Assert.ok(!findbar.hidden, "Findbar should be open now.");
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 1],
+    };
+    let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    await SpecialPowers.pushPrefEnv({ set: [[kPrefModalHighlight, false]] });
+
+    expectedResult = {
+      rectCount: 0,
+      insertCalls: [0, 0],
+      removeCalls: [0, 0],
+    };
+    promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    findbar.clear();
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    findbar.close(true);
+  });
+
+  await SpecialPowers.pushPrefEnv({ set: [[kPrefModalHighlight, true]] });
+});
+
+// Test if highlighting a dark page is detected properly.
+add_task(async function testDarkPageDetection() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    await promiseOpenFindbar(findbar);
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [1, 3],
+      removeCalls: [0, 1],
+    };
+    let promise = promiseTestHighlighterOutput(
+      browser,
+      word,
+      expectedResult,
+      function (node) {
+        Assert.ok(
+          node.style.background.startsWith("rgba(0, 0, 0"),
+          "White HTML page should have a black background color set for the mask"
+        );
+      }
+    );
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    findbar.close(true);
+  });
+
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    await promiseOpenFindbar(findbar);
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 1],
+    };
+
+    await SpecialPowers.spawn(browser, [], async function () {
+      let dwu = content.windowUtils;
+      let uri =
+        "data:text/css;charset=utf-8," +
+        encodeURIComponent(`
+        body {
+          background: maroon radial-gradient(circle, #a01010 0%, #800000 80%) center center / cover no-repeat;
+          color: white;
+        }`);
+      try {
+        dwu.loadSheetUsingURIString(uri, dwu.USER_SHEET);
+      } catch (e) {}
+    });
+
+    let promise = promiseTestHighlighterOutput(
+      browser,
+      word,
+      expectedResult,
+      node => {
+        Assert.ok(
+          node.style.background.startsWith("rgba(255, 255, 255"),
+          "Dark HTML page should have a white background color set for the mask"
+        );
+      }
+    );
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    findbar.close(true);
+  });
+});
+
+add_task(async function testHighlightAllToggle() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    await promiseOpenFindbar(findbar);
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 1],
+    };
+    let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    // We now know we have multiple rectangles highlighted, so it's a good time
+    // to flip the pref.
+    expectedResult = {
+      rectCount: 0,
+      insertCalls: [0, 1],
+      removeCalls: [1, 2],
+    };
+    promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await SpecialPowers.pushPrefEnv({ set: [[kPrefHighlightAll, false]] });
+    await promise;
+
+    // For posterity, let's switch back.
+    expectedResult = {
+      rectCount: 2,
+      insertCalls: [1, 3],
+      removeCalls: [0, 1],
+    };
+    promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await SpecialPowers.pushPrefEnv({ set: [[kPrefHighlightAll, true]] });
+    await promise;
+  });
+});
+
+add_task(async function testXMLDocument() {
+  let url =
+    "data:text/xml;charset=utf-8," +
+    encodeURIComponent(`<?xml version="1.0"?>
+<result>
+  <Title>Example</Title>
+  <Error>Error</Error>
+</result>`);
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+
+    await promiseOpenFindbar(findbar);
+
+    let word = "Example";
+    let expectedResult = {
+      rectCount: 0,
+      insertCalls: [1, 4],
+      removeCalls: [0, 1],
+    };
+    let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    findbar.close(true);
+  });
+});
+
+add_task(async function testHideOnLocationChange() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, url);
+  let browser = tab.linkedBrowser;
+  let findbar = await gBrowser.getFindBar();
+
+  await promiseOpenFindbar(findbar);
+
+  let word = "Roland";
+  let expectedResult = {
+    rectCount: 2,
+    insertCalls: [2, 4],
+    removeCalls: [0, 1],
+  };
+  let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+  await promiseEnterStringIntoFindField(findbar, word);
+  await promise;
+
+  // Now we try to navigate away! (Using the same page)
+  promise = promiseTestHighlighterOutput(browser, word, {
+    rectCount: 0,
+    insertCalls: [0, 0],
+    removeCalls: [1, 2],
+  });
+  BrowserTestUtils.loadURIString(browser, url);
+  await promise;
+
+  BrowserTestUtils.removeTab(tab);
+});
+
+add_task(async function testHideOnClear() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+    await promiseOpenFindbar(findbar);
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 2],
+    };
+    let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+
+    await new Promise(resolve => setTimeout(resolve, kIteratorTimeout));
+    promise = promiseTestHighlighterOutput(browser, "", {
+      rectCount: 0,
+      insertCalls: [0, 0],
+      removeCalls: [1, 2],
+    });
+    findbar.clear();
+    await promise;
+
+    findbar.close(true);
+  });
+});
+
+add_task(async function testRectsAndTexts() {
+  let url =
+    "data:text/html;charset=utf-8," +
+    encodeURIComponent(
+      '<div style="width: 150px; border: 1px solid black">' +
+        "Here are a lot of words Please use find to highlight some words that wrap" +
+        " across a line boundary and see what happens.</div>"
+    );
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+    await promiseOpenFindbar(findbar);
+
+    let word = "words please use find to";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 2],
+    };
+    let promise = promiseTestHighlighterOutput(
+      browser,
+      word,
+      expectedResult,
+      (maskNode, outlineNode) => {
+        let boxes = outlineNode.getElementsByTagName("span");
+        Assert.equal(
+          boxes.length,
+          2,
+          "There should be two outline boxes containing text"
+        );
+        Assert.equal(
+          boxes[0].textContent.trim(),
+          "words",
+          "First text should match"
+        );
+        Assert.equal(
+          boxes[1].textContent.trim(),
+          "Please use find to",
+          "Second word should match"
+        );
+      }
+    );
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+  });
+});
+
+add_task(async function testTooLargeToggle() {
+  let url = kFixtureBaseURL + "file_FinderSample.html";
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = await gBrowser.getFindBar();
+    await promiseOpenFindbar(findbar);
+
+    await SpecialPowers.spawn(browser, [], async function () {
+      let dwu = content.windowUtils;
+      let uri =
+        "data:text/css;charset=utf-8," +
+        encodeURIComponent(`
+        body {
+          min-height: 1234567px;
+        }`);
+      try {
+        dwu.loadSheetUsingURIString(uri, dwu.USER_SHEET);
+      } catch (e) {}
+    });
+
+    let word = "Roland";
+    let expectedResult = {
+      rectCount: 2,
+      insertCalls: [2, 4],
+      removeCalls: [0, 2],
+      // No animations should be triggered when the page is too large.
+      animationCalls: [0, 0],
+    };
+    let promise = promiseTestHighlighterOutput(browser, word, expectedResult);
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+  });
+});
diff --git a/toolkit/modules/tests/browser/browser_FinderHighlighter2.js b/toolkit/modules/tests/browser/browser_FinderHighlighter2.js
new file mode 100644
index 0000000000..1fa026b333
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_FinderHighlighter2.js
@@ -0,0 +1,70 @@
+"use strict";
+
+const kPrefHighlightAll = "findbar.highlightAll";
+const kPrefModalHighlight = "findbar.modalHighlight";
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      [kPrefHighlightAll, true],
+      [kPrefModalHighlight, true],
+    ],
+  });
+});
+
+add_task(async function testIframeOffset() {
+  let url = kFixtureBaseURL + "file_FinderIframeTest.html";
+
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let findbar = gBrowser.getFindBar();
+    await promiseOpenFindbar(findbar);
+
+    let word = "frame";
+    let expectedResult = {
+      rectCount: 12,
+      insertCalls: [2, 4],
+      removeCalls: [0, 2],
+    };
+    let promise = promiseTestHighlighterOutput(
+      browser,
+      word,
+      expectedResult,
+      (maskNode, outlineNode, rects) => {
+        Assert.equal(
+          rects.length,
+          expectedResult.rectCount,
+          "Rect counts should match"
+        );
+        // Checks to guard against regressing this functionality:
+        let expectedOffsets = [
+          { x: 16, y: 60 },
+          { x: 68, y: 104 },
+          { x: 21, y: 215 },
+          { x: 78, y: 264 },
+          { x: 21, y: 375 },
+          { x: 78, y: 424 },
+          { x: 20, y: 534 },
+          { x: 93, y: 534 },
+          { x: 71, y: 577 },
+          { x: 145, y: 577 },
+        ];
+        for (let i = 1, l = rects.length - 1; i < l; ++i) {
+          let rect = rects[i];
+          let expected = expectedOffsets[i - 1];
+          Assert.equal(
+            Math.floor(rect.x),
+            expected.x,
+            "Horizontal offset should match for rect " + i
+          );
+          Assert.equal(
+            Math.floor(rect.y),
+            expected.y,
+            "Vertical offset should match for rect " + i
+          );
+        }
+      }
+    );
+    await promiseEnterStringIntoFindField(findbar, word);
+    await promise;
+  });
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_hidden_textarea.js b/toolkit/modules/tests/browser/browser_Finder_hidden_textarea.js
new file mode 100644
index 0000000000..149bae7666
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_hidden_textarea.js
@@ -0,0 +1,70 @@
+/* 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/. */
+add_task(async function test_bug1174036() {
+  const URI =
+    "<body><textarea>e1</textarea><textarea>e2</textarea><textarea>e3</textarea></body>";
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      // Hide the first textarea.
+      await SpecialPowers.spawn(browser, [], function () {
+        content.document.getElementsByTagName("textarea")[0].style.display =
+          "none";
+      });
+
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      // Find the first 'e' (which should be in the second textarea).
+      let promiseFind = waitForFind();
+      finder.fastFind("e", false, false);
+      let findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_FOUND,
+        "find first string"
+      );
+
+      let firstRect = findResult.rect;
+
+      // Find the second 'e' (in the third textarea).
+      promiseFind = waitForFind();
+      finder.findAgain("e", false, false, false);
+      findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_FOUND,
+        "find second string"
+      );
+      ok(!findResult.rect.equals(firstRect), "found new string");
+
+      // Ensure that we properly wrap to the second textarea.
+      promiseFind = waitForFind();
+      finder.findAgain("e", false, false, false);
+      findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_WRAPPED,
+        "wrapped to first string"
+      );
+      ok(findResult.rect.equals(firstRect), "wrapped to original string");
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_offscreen_text.js b/toolkit/modules/tests/browser/browser_Finder_offscreen_text.js
new file mode 100644
index 0000000000..ea6bb4508f
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_offscreen_text.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_offscreen_text() {
+  // Generate URI of a big DOM that contains the target text at several
+  // line positions (to force some targets to be offscreen).
+  const linesToGenerate = 155;
+  const linesToInsertTargetText = [5, 50, 150];
+  let targetCount = linesToInsertTargetText.length;
+  let t = 0;
+  const TARGET_TEXT = "findthis";
+
+  let URI = "<body>";
+  for (let i = 0; i < linesToGenerate; i++) {
+    URI += i + "<br>";
+    if (t < targetCount && linesToInsertTargetText[t] == i) {
+      URI += TARGET_TEXT;
+      t++;
+    }
+  }
+  URI += "</body>";
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      // Find each of the targets.
+      for (let t = 0; t < targetCount; ++t) {
+        let promiseFind = waitForFind();
+        if (t == 0) {
+          finder.fastFind(TARGET_TEXT, false, false);
+        } else {
+          finder.findAgain(TARGET_TEXT, false, false, false);
+        }
+        let findResult = await promiseFind;
+        is(
+          findResult.result,
+          Ci.nsITypeAheadFind.FIND_FOUND,
+          "Found target " + t
+        );
+      }
+
+      // Find one more time and make sure we wrap.
+      let promiseFind = waitForFind();
+      finder.findAgain(TARGET_TEXT, false, false, false);
+      let findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_WRAPPED,
+        "Wrapped to first target"
+      );
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_overflowed_onscreen.js b/toolkit/modules/tests/browser/browser_Finder_overflowed_onscreen.js
new file mode 100644
index 0000000000..c31014c943
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_overflowed_onscreen.js
@@ -0,0 +1,45 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_vertical_text() {
+  const URI =
+    '<body><div style="max-height: 100px; max-width: 100px; overflow: scroll;"><div style="padding-left: 100px; max-height: 100px; max-width: 200px; overflow: auto;">d<br/><br/><br/><br/>c----------------b<br/><br/><br/><br/>a</div></div></body>';
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      let targets = ["a", "b", "c", "d"];
+
+      for (let i = 0; i < targets.length; ++i) {
+        // Find the target text.
+        let target = targets[i];
+        let promiseFind = waitForFind();
+        finder.fastFind(target, false, false);
+        let findResult = await promiseFind;
+        isnot(
+          findResult.result,
+          Ci.nsITypeAheadFind.FIND_NOTFOUND,
+          "Found target text '" + target + "'."
+        );
+      }
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_overflowed_textarea.js b/toolkit/modules/tests/browser/browser_Finder_overflowed_textarea.js
new file mode 100644
index 0000000000..479ee6c4bb
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_overflowed_textarea.js
@@ -0,0 +1,75 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+add_task(async function test_offscreen_text() {
+  // Generate URI of a big DOM that contains the target text
+  // within a textarea at several line positions (to force
+  // some targets to be overflowed).
+  const linesToGenerate = 155;
+  const linesToInsertTargetText = [5, 50, 150];
+  const targetCount = linesToInsertTargetText.length;
+  let t = 0;
+  const TARGET_TEXT = "findthis";
+
+  let URI = "<body><textarea>";
+  for (let i = 0; i < linesToGenerate; i++) {
+    URI += i + " ";
+    if (t < targetCount && linesToInsertTargetText[t] == i) {
+      URI += TARGET_TEXT;
+      t++;
+    }
+    URI += "\n";
+  }
+  URI += "</textarea></body>";
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      // Find each of the targets.
+      for (let t = 0; t < targetCount; ++t) {
+        let promiseFind = waitForFind();
+        if (t == 0) {
+          finder.fastFind(TARGET_TEXT, false, false);
+        } else {
+          finder.findAgain(TARGET_TEXT, false, false, false);
+        }
+        let findResult = await promiseFind;
+        is(
+          findResult.result,
+          Ci.nsITypeAheadFind.FIND_FOUND,
+          "Found target " + t
+        );
+      }
+
+      // Find one more time and make sure we wrap.
+      let promiseFind = waitForFind();
+      finder.findAgain(TARGET_TEXT, false, false, false);
+      let findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_WRAPPED,
+        "Wrapped to first target"
+      );
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_pointer_events_none.js b/toolkit/modules/tests/browser/browser_Finder_pointer_events_none.js
new file mode 100644
index 0000000000..2e6e31d4cf
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_pointer_events_none.js
@@ -0,0 +1,39 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_offscreen_text() {
+  const URI = '<body><div style="pointer-events:none">find this</div></body>';
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      // Find the target text.
+      let promiseFind = waitForFind();
+      finder.fastFind("find this", false, false);
+      let findResult = await promiseFind;
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_FOUND,
+        "Found target text."
+      );
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_skip_invisible_and_option.js b/toolkit/modules/tests/browser/browser_Finder_skip_invisible_and_option.js
new file mode 100644
index 0000000000..c133bbb613
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_skip_invisible_and_option.js
@@ -0,0 +1,132 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_skip_invisible() {
+  const URI = `
+    <body>
+      <div>
+        a
+        <div style="visibility:hidden;">a</div>
+        <div style="visibility: hidden"><span style="visibility: visible">a</div>
+        <select>
+          <option>a</option>
+        </select>
+        <select size=2>
+          <option>a</option>
+          <option>a</option>
+        </select>
+        <input placeholder="a">
+      </body>`;
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      // Find the target text. There should be three results.
+      let target = "a";
+      let promiseFind = waitForFind();
+      finder.fastFind(target, false, false);
+      let findResult = await promiseFind;
+
+      // Check the results and repeat four times. After the final repeat, make
+      // sure we've wrapped to the beginning.
+      let i = 0;
+      for (; i < 4; i++) {
+        isnot(
+          findResult.result,
+          Ci.nsITypeAheadFind.FIND_NOTFOUND,
+          "Should find target text '" + target + "' instance " + (i + 1) + "."
+        );
+
+        promiseFind = waitForFind();
+        finder.findAgain("a", false, false, false);
+        findResult = await promiseFind;
+      }
+      is(
+        findResult.result,
+        Ci.nsITypeAheadFind.FIND_WRAPPED,
+        "After " + (i + 1) + " searches, we should wrap to first target text."
+      );
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
+
+add_task(async function test_find_anon_content() {
+  const URI = `
+    <!doctype html>
+    <style>
+      div::before { content: "before content"; }
+      div::after { content: "after content"; }
+      span::after { content: ","; }
+    </style>
+    <div> </div>
+    <img alt="Some fallback text">
+    <input type="submit" value="Some button text">
+    <input type="password" value="password">
+    <p>1<span></span>234</p>
+
+  `;
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      async function assertFindable(text, findable = true) {
+        let promiseFind = waitForFind();
+        finder.fastFind(text, false, false);
+        let findResult = await promiseFind;
+        is(
+          findResult.result,
+          findable
+            ? Ci.nsITypeAheadFind.FIND_FOUND
+            : Ci.nsITypeAheadFind.FIND_NOTFOUND,
+          `${text} should ${findable ? "" : "not "}be findable`
+        );
+      }
+
+      await assertFindable("before content");
+      await assertFindable("after content");
+      await assertFindable("fallback text");
+      await assertFindable("button text");
+      await assertFindable("password", false);
+
+      // TODO(emilio): In an ideal world we could select the comma as well and
+      // then you'd find it with "1,234" instead...
+      await assertFindable("1234");
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Finder_vertical_text.js b/toolkit/modules/tests/browser/browser_Finder_vertical_text.js
new file mode 100644
index 0000000000..c20c4ea8f6
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Finder_vertical_text.js
@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_vertical_text() {
+  const URI =
+    '<body><div style="writing-mode: vertical-rl">vertical-rl</div><div style="writing-mode: vertical-lr">vertical-lr</div><div style="writing-mode: sideways-rl">sideways-rl</div><div style="writing-mode: sideways-lr">sideways-lr</div></body>';
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "data:text/html;charset=utf-8," + encodeURIComponent(URI),
+    },
+    async function (browser) {
+      let finder = browser.finder;
+      let listener = {
+        onFindResult() {
+          ok(false, "callback wasn't replaced");
+        },
+      };
+      finder.addResultListener(listener);
+
+      function waitForFind() {
+        return new Promise(resolve => {
+          listener.onFindResult = resolve;
+        });
+      }
+
+      let targets = [
+        // Full matches use one path in our find code.
+        "vertical-rl",
+        "vertical-lr",
+        "sideways-rl",
+        "sideways-lr",
+        // Partial matches use a second path in our find code.
+        "l-r",
+        "l-l",
+        "s-r",
+        "s-l",
+      ];
+
+      for (let i = 0; i < targets.length; ++i) {
+        // Find the target text.
+        let target = targets[i];
+        let promiseFind = waitForFind();
+        finder.fastFind(target, false, false);
+        let findResult = await promiseFind;
+
+        // We check the logical inversion of not not found, because found and wrapped are
+        // two different correct results, but not found is the only incorrect result.
+        isnot(
+          findResult.result,
+          Ci.nsITypeAheadFind.FIND_NOTFOUND,
+          "Found target text '" + target + "'."
+        );
+      }
+
+      finder.removeResultListener(listener);
+    }
+  );
+});
diff --git a/toolkit/modules/tests/browser/browser_Geometry.js b/toolkit/modules/tests/browser/browser_Geometry.js
new file mode 100644
index 0000000000..eae19e3d59
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Geometry.js
@@ -0,0 +1,134 @@
+/* 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 { Point, Rect } = ChromeUtils.importESModule(
+  "resource://gre/modules/Geometry.sys.mjs"
+);
+
+function test() {
+  ok(Rect, "Rect class exists");
+  for (var fname in tests) {
+    tests[fname]();
+  }
+}
+
+var tests = {
+  testGetDimensions() {
+    let r = new Rect(5, 10, 100, 50);
+    ok(r.left == 5, "rect has correct left value");
+    ok(r.top == 10, "rect has correct top value");
+    ok(r.right == 105, "rect has correct right value");
+    ok(r.bottom == 60, "rect has correct bottom value");
+    ok(r.width == 100, "rect has correct width value");
+    ok(r.height == 50, "rect has correct height value");
+    ok(r.x == 5, "rect has correct x value");
+    ok(r.y == 10, "rect has correct y value");
+  },
+
+  testIsEmpty() {
+    let r = new Rect(0, 0, 0, 10);
+    ok(r.isEmpty(), "rect with nonpositive width is empty");
+    r = new Rect(0, 0, 10, 0);
+    ok(r.isEmpty(), "rect with nonpositive height is empty");
+    r = new Rect(0, 0, 10, 10);
+    ok(!r.isEmpty(), "rect with positive dimensions is not empty");
+  },
+
+  testRestrictTo() {
+    let r1 = new Rect(10, 10, 100, 100);
+    let r2 = new Rect(50, 50, 100, 100);
+    r1.restrictTo(r2);
+    ok(r1.equals(new Rect(50, 50, 60, 60)), "intersection is non-empty");
+
+    r1 = new Rect(10, 10, 100, 100);
+    r2 = new Rect(120, 120, 100, 100);
+    r1.restrictTo(r2);
+    ok(r1.isEmpty(), "intersection is empty");
+
+    r1 = new Rect(10, 10, 100, 100);
+    r2 = new Rect(0, 0, 0, 0);
+    r1.restrictTo(r2);
+    ok(r1.isEmpty(), "intersection of rect and empty is empty");
+
+    r1 = new Rect(0, 0, 0, 0);
+    r2 = new Rect(0, 0, 0, 0);
+    r1.restrictTo(r2);
+    ok(r1.isEmpty(), "intersection of empty and empty is empty");
+  },
+
+  testExpandToContain() {
+    let r1 = new Rect(10, 10, 100, 100);
+    let r2 = new Rect(50, 50, 100, 100);
+    r1.expandToContain(r2);
+    ok(
+      r1.equals(new Rect(10, 10, 140, 140)),
+      "correct expandToContain on intersecting rectangles"
+    );
+
+    r1 = new Rect(10, 10, 100, 100);
+    r2 = new Rect(120, 120, 100, 100);
+    r1.expandToContain(r2);
+    ok(
+      r1.equals(new Rect(10, 10, 210, 210)),
+      "correct expandToContain on non-intersecting rectangles"
+    );
+
+    r1 = new Rect(10, 10, 100, 100);
+    r2 = new Rect(0, 0, 0, 0);
+    r1.expandToContain(r2);
+    ok(
+      r1.equals(new Rect(10, 10, 100, 100)),
+      "expandToContain of rect and empty is rect"
+    );
+
+    r1 = new Rect(10, 10, 0, 0);
+    r2 = new Rect(0, 0, 0, 0);
+    r1.expandToContain(r2);
+    ok(r1.isEmpty(), "expandToContain of empty and empty is empty");
+  },
+
+  testSubtract: function testSubtract() {
+    function equals(rects1, rects2) {
+      return (
+        rects1.length == rects2.length &&
+        rects1.every(function (r, i) {
+          return r.equals(rects2[i]);
+        })
+      );
+    }
+
+    let r1 = new Rect(0, 0, 100, 100);
+    let r2 = new Rect(500, 500, 100, 100);
+    ok(
+      equals(r1.subtract(r2), [r1]),
+      "subtract area outside of region yields same region"
+    );
+
+    r1 = new Rect(0, 0, 100, 100);
+    r2 = new Rect(-10, -10, 50, 120);
+    ok(
+      equals(r1.subtract(r2), [new Rect(40, 0, 60, 100)]),
+      "subtracting vertical bar from edge leaves one rect"
+    );
+
+    r1 = new Rect(0, 0, 100, 100);
+    r2 = new Rect(-10, -10, 120, 50);
+    ok(
+      equals(r1.subtract(r2), [new Rect(0, 40, 100, 60)]),
+      "subtracting horizontal bar from edge leaves one rect"
+    );
+
+    r1 = new Rect(0, 0, 100, 100);
+    r2 = new Rect(40, 40, 20, 20);
+    ok(
+      equals(r1.subtract(r2), [
+        new Rect(0, 0, 40, 100),
+        new Rect(40, 0, 20, 40),
+        new Rect(40, 60, 20, 40),
+        new Rect(60, 0, 40, 100),
+      ]),
+      "subtracting rect in middle leaves union of rects"
+    );
+  },
+};
diff --git a/toolkit/modules/tests/browser/browser_InlineSpellChecker.js b/toolkit/modules/tests/browser/browser_InlineSpellChecker.js
new file mode 100644
index 0000000000..c931615091
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_InlineSpellChecker.js
@@ -0,0 +1,47 @@
+var InlineSpellChecker;
+var SpellCheckHelper;
+
+function test() {
+  let tempScope = ChromeUtils.importESModule(
+    "resource://gre/modules/InlineSpellChecker.sys.mjs"
+  );
+  InlineSpellChecker = tempScope.InlineSpellChecker;
+  SpellCheckHelper = tempScope.SpellCheckHelper;
+
+  ok(InlineSpellChecker, "InlineSpellChecker class exists");
+  for (var fname in tests) {
+    tests[fname]();
+  }
+}
+
+var tests = {
+  testFlagsForInputs() {
+    const HTML_NS = "http://www.w3.org/1999/xhtml";
+    const { INPUT, EDITABLE, TEXTINPUT, NUMERIC, PASSWORD, SPELLCHECKABLE } =
+      SpellCheckHelper;
+    const kExpectedResults = {
+      text: INPUT | EDITABLE | TEXTINPUT | SPELLCHECKABLE,
+      password: INPUT | EDITABLE | TEXTINPUT | PASSWORD,
+      search: INPUT | EDITABLE | TEXTINPUT | SPELLCHECKABLE,
+      url: INPUT | EDITABLE | TEXTINPUT,
+      tel: INPUT | EDITABLE | TEXTINPUT,
+      email: INPUT | EDITABLE | TEXTINPUT,
+      number: INPUT | EDITABLE | TEXTINPUT | NUMERIC,
+      checkbox: INPUT,
+      radio: INPUT,
+    };
+
+    for (let [type, expectedFlags] of Object.entries(kExpectedResults)) {
+      let input = document.createElementNS(HTML_NS, "input");
+      input.type = type;
+      let actualFlags = SpellCheckHelper.isEditable(input, window);
+      is(
+        actualFlags,
+        expectedFlags,
+        `For input type "${type}" expected flags ${
+          "0x" + expectedFlags.toString(16)
+        }; got ${"0x" + actualFlags.toString(16)}`
+      );
+    }
+  },
+};
diff --git a/toolkit/modules/tests/browser/browser_Troubleshoot.js b/toolkit/modules/tests/browser/browser_Troubleshoot.js
new file mode 100644
index 0000000000..751b1954e1
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_Troubleshoot.js
@@ -0,0 +1,1316 @@
+/* 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/. */
+
+// Ideally this would be an xpcshell test, but Troubleshoot relies on things
+// that aren't initialized outside of a XUL app environment like AddonManager
+// and the "@mozilla.org/xre/app-info;1" component.
+
+const { Troubleshoot } = ChromeUtils.importESModule(
+  "resource://gre/modules/Troubleshoot.sys.mjs"
+);
+const { sinon } = ChromeUtils.importESModule(
+  "resource://testing-common/Sinon.sys.mjs"
+);
+
+const { FeatureGate } = ChromeUtils.importESModule(
+  "resource://featuregates/FeatureGate.sys.mjs"
+);
+const { PreferenceExperiments } = ChromeUtils.importESModule(
+  "resource://normandy/lib/PreferenceExperiments.sys.mjs"
+);
+const { PreferenceRollouts } = ChromeUtils.importESModule(
+  "resource://normandy/lib/PreferenceRollouts.sys.mjs"
+);
+const { AddonStudies } = ChromeUtils.importESModule(
+  "resource://normandy/lib/AddonStudies.sys.mjs"
+);
+const { NormandyTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/NormandyTestUtils.sys.mjs"
+);
+
+NormandyTestUtils.init({ Assert });
+
+add_task(async function snapshotSchema() {
+  let snapshot = await Troubleshoot.snapshot();
+  try {
+    validateObject(snapshot, SNAPSHOT_SCHEMA);
+    ok(true, "The snapshot should conform to the schema.");
+  } catch (err) {
+    ok(false, "Schema mismatch, " + err);
+  }
+});
+
+add_task(async function experimentalFeatures() {
+  let featureGates = await FeatureGate.all();
+  ok(featureGates.length, "Should be at least one FeatureGate");
+
+  let snapshot = await Troubleshoot.snapshot();
+  for (let i = 0; i < snapshot.experimentalFeatures.length; i++) {
+    let experimentalFeature = snapshot.experimentalFeatures[i];
+    is(
+      experimentalFeature[0],
+      featureGates[i].title,
+      "The first item in the array should be the title's l10n-id of the FeatureGate"
+    );
+    is(
+      experimentalFeature[1],
+      featureGates[i].preference,
+      "The second item in the array should be the preference name for the FeatureGate"
+    );
+    is(
+      experimentalFeature[2],
+      Services.prefs.getBoolPref(featureGates[i].preference),
+      "The third item in the array should be the preference value of the FeatureGate"
+    );
+  }
+});
+
+add_task(async function modifiedPreferences() {
+  let prefs = [
+    "javascript.troubleshoot",
+    "troubleshoot.foo",
+    "network.proxy.troubleshoot",
+    "print.print_to_filename",
+  ];
+  prefs.forEach(function (p) {
+    Services.prefs.setBoolPref(p, true);
+    is(Services.prefs.getBoolPref(p), true, "The pref should be set: " + p);
+  });
+  Services.prefs.setCharPref("dom.push.userAgentID", "testvalue");
+  let snapshot = await Troubleshoot.snapshot();
+  let p = snapshot.modifiedPreferences;
+  is(
+    p["javascript.troubleshoot"],
+    true,
+    "The pref should be present because it's in the allowed prefs " +
+      "and not in the pref regexes that are disallowed."
+  );
+  ok(
+    !("troubleshoot.foo" in p),
+    "The pref should be absent because it's not in the allowed prefs."
+  );
+  ok(
+    !("network.proxy.troubleshoot" in p),
+    "The pref should be absent because it's in the pref regexes " +
+      "that are disallowed."
+  );
+  ok(
+    !("dom.push.userAgentID" in p),
+    "The pref should be absent because it's in the pref regexes " +
+      "that are disallowed."
+  );
+  ok(
+    !("print.print_to_filename" in p),
+    "The pref should be absent because it's not in the allowed prefs."
+  );
+  prefs.forEach(p => Services.prefs.deleteBranch(p));
+  Services.prefs.clearUserPref("dom.push.userAgentID");
+});
+
+add_task(async function unicodePreferences() {
+  let name = "font.name.sans-serif.x-western";
+  let utf8Value = "\xc4\x8capk\xc5\xafv Krasopis";
+  let unicodeValue = "\u010Capk\u016Fv Krasopis";
+
+  // set/getCharPref work with 8bit strings (utf8)
+  Services.prefs.setCharPref(name, utf8Value);
+
+  let snapshot = await Troubleshoot.snapshot();
+  let p = snapshot.modifiedPreferences;
+  is(p[name], unicodeValue, "The pref should have correct Unicode value.");
+  Services.prefs.deleteBranch(name);
+});
+
+add_task(async function printingPreferences() {
+  let prefs = [
+    "javascript.print_to_filename",
+    "print.print_bgimages",
+    "print.print_to_filename",
+  ];
+  prefs.forEach(function (p) {
+    Services.prefs.setBoolPref(p, true);
+    is(Services.prefs.getBoolPref(p), true, "The pref should be set: " + p);
+  });
+  let snapshot = await Troubleshoot.snapshot();
+  let p = snapshot.printingPreferences;
+  is(p["print.print_bgimages"], true, "The pref should be present");
+  ok(
+    !("print.print_to_filename" in p),
+    "The pref should not be present (sensitive)"
+  );
+  ok(
+    !("javascript.print_to_filename" in p),
+    "The pref should be absent because it's not a print pref."
+  );
+  prefs.forEach(p => Services.prefs.deleteBranch(p));
+});
+
+add_task(function normandy() {
+  const {
+    preferenceStudyFactory,
+    branchedAddonStudyFactory,
+    preferenceRolloutFactory,
+  } = NormandyTestUtils.factories;
+
+  return NormandyTestUtils.decorate(
+    PreferenceExperiments.withMockExperiments([
+      preferenceStudyFactory({
+        userFacingName: "Test Pref Study B",
+        branch: "test-branch-pref",
+      }),
+      preferenceStudyFactory({
+        userFacingName: "Test Pref Study A",
+        branch: "test-branch-pref",
+      }),
+    ]),
+    AddonStudies.withStudies([
+      branchedAddonStudyFactory({
+        userFacingName: "Test Addon Study B",
+        branch: "test-branch-addon",
+      }),
+      branchedAddonStudyFactory({
+        userFacingName: "Test Addon Study A",
+        branch: "test-branch-addon",
+      }),
+    ]),
+    PreferenceRollouts.withTestMock({
+      rollouts: [
+        preferenceRolloutFactory({
+          statue: "ACTIVE",
+          slug: "test-pref-rollout-b",
+        }),
+        preferenceRolloutFactory({
+          statue: "ACTIVE",
+          slug: "test-pref-rollout-a",
+        }),
+      ],
+    }),
+    async function testNormandyInfoInTroubleshooting({
+      prefExperiments,
+      addonStudies,
+      prefRollouts,
+    }) {
+      let snapshot = await Troubleshoot.snapshot();
+      let info = snapshot.normandy;
+      // The order should be flipped, since each category is sorted by slug.
+      Assert.deepEqual(
+        info.prefStudies,
+        [prefExperiments[1], prefExperiments[0]],
+        "prefs studies should exist in the right order"
+      );
+      Assert.deepEqual(
+        info.addonStudies,
+        [addonStudies[1], addonStudies[0]],
+        "addon studies should exist in the right order"
+      );
+      Assert.deepEqual(
+        info.prefRollouts,
+        [prefRollouts[1], prefRollouts[0]],
+        "pref rollouts should exist in the right order"
+      );
+    }
+  )();
+});
+
+add_task(function normandyErrorHandling() {
+  return NormandyTestUtils.decorate(
+    NormandyTestUtils.withStub(PreferenceExperiments, "getAllActive", {
+      returnValue: Promise.reject("Expected error - PreferenceExperiments"),
+    }),
+    NormandyTestUtils.withStub(AddonStudies, "getAllActive", {
+      returnValue: Promise.reject("Expected error - AddonStudies"),
+    }),
+    NormandyTestUtils.withStub(PreferenceRollouts, "getAllActive", {
+      returnValue: Promise.reject("Expected error - PreferenceRollouts"),
+    }),
+    async function testNormandyErrorHandling() {
+      let consoleEndFn = TestUtils.listenForConsoleMessages();
+      let snapshot = await Troubleshoot.snapshot();
+      let info = snapshot.normandy;
+      Assert.deepEqual(
+        info.prefStudies,
+        [],
+        "prefs studies should be an empty list if there is an error"
+      );
+      Assert.deepEqual(
+        info.addonStudies,
+        [],
+        "addon studies should be an empty list if there is an error"
+      );
+      Assert.deepEqual(
+        info.prefRollouts,
+        [],
+        "pref rollouts should be an empty list if there is an error"
+      );
+      let msgs = await consoleEndFn();
+      let expectedSet = new Set([
+        /Expected error - PreferenceExperiments/,
+        /Expected error - AddonStudies/,
+        /Expected error - PreferenceRollouts/,
+      ]);
+
+      for (let msg of msgs) {
+        msg = msg.wrappedJSObject;
+        if (msg.level != "error") {
+          continue;
+        }
+
+        let msgContents = msg.arguments[0];
+        for (let expected of expectedSet) {
+          if (expected.test(msgContents)) {
+            expectedSet.delete(expected);
+            break;
+          }
+        }
+      }
+
+      Assert.equal(
+        expectedSet.size,
+        0,
+        "Should have no messages left in the expected set"
+      );
+    }
+  )();
+});
+
+// This is inspired by JSON Schema, or by the example on its Wikipedia page
+// anyway.
+const SNAPSHOT_SCHEMA = {
+  type: "object",
+  required: true,
+  properties: {
+    application: {
+      required: true,
+      type: "object",
+      properties: {
+        name: {
+          required: true,
+          type: "string",
+        },
+        version: {
+          required: true,
+          type: "string",
+        },
+        buildID: {
+          required: true,
+          type: "string",
+        },
+        distributionID: {
+          required: true,
+          type: "string",
+        },
+        userAgent: {
+          required: true,
+          type: "string",
+        },
+        osVersion: {
+          required: true,
+          type: "string",
+        },
+        osTheme: {
+          type: "string",
+        },
+        rosetta: {
+          required: false,
+          type: "boolean",
+        },
+        vendor: {
+          type: "string",
+        },
+        updateChannel: {
+          type: "string",
+        },
+        supportURL: {
+          type: "string",
+        },
+        launcherProcessState: {
+          type: "number",
+        },
+        remoteAutoStart: {
+          type: "boolean",
+          required: true,
+        },
+        fissionAutoStart: {
+          type: "boolean",
+        },
+        fissionDecisionStatus: {
+          type: "string",
+        },
+        numTotalWindows: {
+          type: "number",
+        },
+        numFissionWindows: {
+          type: "number",
+        },
+        numRemoteWindows: {
+          type: "number",
+        },
+        policiesStatus: {
+          type: "number",
+        },
+        keyLocationServiceGoogleFound: {
+          type: "boolean",
+        },
+        keySafebrowsingGoogleFound: {
+          type: "boolean",
+        },
+        keyMozillaFound: {
+          type: "boolean",
+        },
+        safeMode: {
+          type: "boolean",
+        },
+        memorySizeBytes: {
+          type: "number",
+        },
+        diskAvailableBytes: {
+          type: "number",
+        },
+      },
+    },
+    crashes: {
+      required: false,
+      type: "object",
+      properties: {
+        pending: {
+          required: true,
+          type: "number",
+        },
+        submitted: {
+          required: true,
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              id: {
+                required: true,
+                type: "string",
+              },
+              date: {
+                required: true,
+                type: "number",
+              },
+              pending: {
+                required: true,
+                type: "boolean",
+              },
+            },
+          },
+        },
+      },
+    },
+    addons: {
+      required: true,
+      type: "array",
+      items: {
+        type: "object",
+        properties: {
+          name: {
+            required: true,
+            type: "string",
+          },
+          type: {
+            required: true,
+            type: "string",
+          },
+          version: {
+            required: true,
+            type: "string",
+          },
+          id: {
+            required: true,
+            type: "string",
+          },
+          isActive: {
+            required: true,
+            type: "boolean",
+          },
+        },
+      },
+    },
+    securitySoftware: {
+      required: false,
+      type: "object",
+      properties: {
+        registeredAntiVirus: {
+          required: true,
+          type: "string",
+        },
+        registeredAntiSpyware: {
+          required: true,
+          type: "string",
+        },
+        registeredFirewall: {
+          required: true,
+          type: "string",
+        },
+      },
+    },
+    features: {
+      required: true,
+      type: "array",
+      items: {
+        type: "object",
+        properties: {
+          name: {
+            required: true,
+            type: "string",
+          },
+          version: {
+            required: true,
+            type: "string",
+          },
+          id: {
+            required: true,
+            type: "string",
+          },
+        },
+      },
+    },
+    processes: {
+      required: true,
+      type: "object",
+      properties: {
+        maxWebContentProcesses: {
+          required: true,
+          type: "number",
+        },
+        remoteTypes: {
+          required: true,
+          type: "object",
+        },
+      },
+    },
+    experimentalFeatures: {
+      required: true,
+      type: "array",
+    },
+    environmentVariables: {
+      required: true,
+      type: "object",
+    },
+    modifiedPreferences: {
+      required: true,
+      type: "object",
+    },
+    printingPreferences: {
+      required: true,
+      type: "object",
+    },
+    lockedPreferences: {
+      required: true,
+      type: "object",
+      properties: {
+        "fission.autostart": {
+          required: false,
+          type: "boolean",
+        },
+        "fission.autostart.session": {
+          required: false,
+          type: "boolean",
+        },
+      },
+    },
+    places: {
+      required: true,
+      type: "array",
+      items: {
+        type: "object",
+        items: {
+          entity: {
+            required: true,
+            type: "string",
+          },
+          count: {
+            required: true,
+            type: "number",
+          },
+          sizeBytes: {
+            required: true,
+            type: "number",
+          },
+          sizePerc: {
+            required: true,
+            type: "number",
+          },
+          efficiencyPerc: {
+            required: true,
+            type: "number",
+          },
+          sequentialityPerc: {
+            required: true,
+            type: "number",
+          },
+        },
+      },
+    },
+    graphics: {
+      required: true,
+      type: "object",
+      properties: {
+        numTotalWindows: {
+          required: true,
+          type: "number",
+        },
+        numAcceleratedWindows: {
+          required: true,
+          type: "number",
+        },
+        graphicsDevicePixelRatios: {
+          type: "array",
+          items: {
+            type: "number",
+          },
+        },
+        windowLayerManagerType: {
+          type: "string",
+        },
+        windowLayerManagerRemote: {
+          type: "boolean",
+        },
+        numAcceleratedWindowsMessage: {
+          type: "object",
+          properties: {
+            key: {
+              required: true,
+              type: "string",
+            },
+            args: {
+              required: false,
+              type: "object",
+            },
+          },
+        },
+        adapterDescription: {
+          type: "string",
+        },
+        adapterVendorID: {
+          type: "string",
+        },
+        adapterDeviceID: {
+          type: "string",
+        },
+        adapterSubsysID: {
+          type: "string",
+        },
+        adapterRAM: {
+          type: "number",
+        },
+        adapterDrivers: {
+          type: "string",
+        },
+        driverVendor: {
+          type: "string",
+        },
+        driverVersion: {
+          type: "string",
+        },
+        driverDate: {
+          type: "string",
+        },
+        adapterDescription2: {
+          type: "string",
+        },
+        adapterVendorID2: {
+          type: "string",
+        },
+        adapterDeviceID2: {
+          type: "string",
+        },
+        adapterSubsysID2: {
+          type: "string",
+        },
+        adapterRAM2: {
+          type: "number",
+        },
+        adapterDrivers2: {
+          type: "string",
+        },
+        driverVendor2: {
+          type: "string",
+        },
+        driverVersion2: {
+          type: "string",
+        },
+        driverDate2: {
+          type: "string",
+        },
+        isGPU2Active: {
+          type: "boolean",
+        },
+        direct2DEnabled: {
+          type: "boolean",
+        },
+        directWriteEnabled: {
+          type: "boolean",
+        },
+        directWriteVersion: {
+          type: "string",
+        },
+        clearTypeParameters: {
+          type: "string",
+        },
+        webgl1Renderer: {
+          type: "string",
+        },
+        webgl1Version: {
+          type: "string",
+        },
+        webgl1DriverExtensions: {
+          type: "string",
+        },
+        webgl1Extensions: {
+          type: "string",
+        },
+        webgl1WSIInfo: {
+          type: "string",
+        },
+        webgl2Renderer: {
+          type: "string",
+        },
+        webgl2Version: {
+          type: "string",
+        },
+        webgl2DriverExtensions: {
+          type: "string",
+        },
+        webgl2Extensions: {
+          type: "string",
+        },
+        webgl2WSIInfo: {
+          type: "string",
+        },
+        webgpuDefaultAdapter: {
+          type: "object",
+        },
+        webgpuFallbackAdapter: {
+          type: "object",
+        },
+        info: {
+          type: "object",
+        },
+        failures: {
+          type: "object",
+          properties: {
+            key: {
+              required: true,
+              type: "string",
+            },
+            args: {
+              required: false,
+              type: "object",
+            },
+          },
+        },
+        indices: {
+          type: "array",
+          items: {
+            type: "number",
+          },
+        },
+        featureLog: {
+          type: "object",
+        },
+        crashGuards: {
+          type: "array",
+        },
+        direct2DEnabledMessage: {
+          type: "object",
+          properties: {
+            key: {
+              required: true,
+              type: "string",
+            },
+            args: {
+              required: false,
+              type: "object",
+            },
+          },
+        },
+        targetFrameRate: {
+          type: "number",
+        },
+        windowProtocol: {
+          type: "string",
+        },
+        desktopEnvironment: {
+          type: "string",
+        },
+      },
+    },
+    media: {
+      required: true,
+      type: "object",
+      properties: {
+        currentAudioBackend: {
+          required: true,
+          type: "string",
+        },
+        currentMaxAudioChannels: {
+          required: true,
+          type: "number",
+        },
+        currentPreferredSampleRate: {
+          required: true,
+          type: "number",
+        },
+        audioOutputDevices: {
+          required: true,
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              name: {
+                required: true,
+                type: "string",
+              },
+              groupId: {
+                required: true,
+                type: "string",
+              },
+              vendor: {
+                required: true,
+                type: "string",
+              },
+              type: {
+                required: true,
+                type: "number",
+              },
+              state: {
+                required: true,
+                type: "number",
+              },
+              preferred: {
+                required: true,
+                type: "number",
+              },
+              supportedFormat: {
+                required: true,
+                type: "number",
+              },
+              defaultFormat: {
+                required: true,
+                type: "number",
+              },
+              maxChannels: {
+                required: true,
+                type: "number",
+              },
+              defaultRate: {
+                required: true,
+                type: "number",
+              },
+              maxRate: {
+                required: true,
+                type: "number",
+              },
+              minRate: {
+                required: true,
+                type: "number",
+              },
+              maxLatency: {
+                required: true,
+                type: "number",
+              },
+              minLatency: {
+                required: true,
+                type: "number",
+              },
+            },
+          },
+        },
+        audioInputDevices: {
+          required: true,
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              name: {
+                required: true,
+                type: "string",
+              },
+              groupId: {
+                required: true,
+                type: "string",
+              },
+              vendor: {
+                required: true,
+                type: "string",
+              },
+              type: {
+                required: true,
+                type: "number",
+              },
+              state: {
+                required: true,
+                type: "number",
+              },
+              preferred: {
+                required: true,
+                type: "number",
+              },
+              supportedFormat: {
+                required: true,
+                type: "number",
+              },
+              defaultFormat: {
+                required: true,
+                type: "number",
+              },
+              maxChannels: {
+                required: true,
+                type: "number",
+              },
+              defaultRate: {
+                required: true,
+                type: "number",
+              },
+              maxRate: {
+                required: true,
+                type: "number",
+              },
+              minRate: {
+                required: true,
+                type: "number",
+              },
+              maxLatency: {
+                required: true,
+                type: "number",
+              },
+              minLatency: {
+                required: true,
+                type: "number",
+              },
+            },
+          },
+        },
+        codecSupportInfo: {
+          required: false,
+          type: "string",
+        },
+      },
+    },
+    accessibility: {
+      required: true,
+      type: "object",
+      properties: {
+        isActive: {
+          required: true,
+          type: "boolean",
+        },
+        forceDisabled: {
+          type: "number",
+        },
+        handlerUsed: {
+          type: "boolean",
+        },
+        instantiator: {
+          type: "string",
+        },
+      },
+    },
+    libraryVersions: {
+      required: true,
+      type: "object",
+      properties: {
+        NSPR: {
+          required: true,
+          type: "object",
+          properties: {
+            minVersion: {
+              required: true,
+              type: "string",
+            },
+            version: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+        NSS: {
+          required: true,
+          type: "object",
+          properties: {
+            minVersion: {
+              required: true,
+              type: "string",
+            },
+            version: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+        NSSUTIL: {
+          required: true,
+          type: "object",
+          properties: {
+            minVersion: {
+              required: true,
+              type: "string",
+            },
+            version: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+        NSSSSL: {
+          required: true,
+          type: "object",
+          properties: {
+            minVersion: {
+              required: true,
+              type: "string",
+            },
+            version: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+        NSSSMIME: {
+          required: true,
+          type: "object",
+          properties: {
+            minVersion: {
+              required: true,
+              type: "string",
+            },
+            version: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+      },
+    },
+    userJS: {
+      required: true,
+      type: "object",
+      properties: {
+        exists: {
+          required: true,
+          type: "boolean",
+        },
+      },
+    },
+    sandbox: {
+      required: false,
+      type: "object",
+      properties: {
+        hasSeccompBPF: {
+          required: AppConstants.platform == "linux",
+          type: "boolean",
+        },
+        hasSeccompTSync: {
+          required: AppConstants.platform == "linux",
+          type: "boolean",
+        },
+        hasUserNamespaces: {
+          required: AppConstants.platform == "linux",
+          type: "boolean",
+        },
+        hasPrivilegedUserNamespaces: {
+          required: AppConstants.platform == "linux",
+          type: "boolean",
+        },
+        canSandboxContent: {
+          required: false,
+          type: "boolean",
+        },
+        canSandboxMedia: {
+          required: false,
+          type: "boolean",
+        },
+        contentSandboxLevel: {
+          required: AppConstants.MOZ_SANDBOX,
+          type: "number",
+        },
+        effectiveContentSandboxLevel: {
+          required: AppConstants.MOZ_SANDBOX,
+          type: "number",
+        },
+        contentWin32kLockdownState: {
+          required: AppConstants.MOZ_SANDBOX,
+          type: "string",
+        },
+        supportSandboxGpuLevel: {
+          required: AppConstants.MOZ_SANDBOX,
+          type: "number",
+        },
+        syscallLog: {
+          required: AppConstants.platform == "linux",
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              index: {
+                required: true,
+                type: "number",
+              },
+              pid: {
+                required: true,
+                type: "number",
+              },
+              tid: {
+                required: true,
+                type: "number",
+              },
+              procType: {
+                required: true,
+                type: "string",
+              },
+              syscall: {
+                required: true,
+                type: "number",
+              },
+              args: {
+                required: true,
+                type: "array",
+                items: {
+                  type: "string",
+                },
+              },
+            },
+          },
+        },
+      },
+    },
+    startupCache: {
+      required: false,
+      type: "object",
+      properties: {
+        DiskCachePath: {
+          required: true,
+          type: "string",
+        },
+        IgnoreDiskCache: {
+          required: true,
+          type: "boolean",
+        },
+        FoundDiskCacheOnInit: {
+          required: true,
+          type: "boolean",
+        },
+        WroteToDiskCache: {
+          required: true,
+          type: "boolean",
+        },
+      },
+    },
+    intl: {
+      required: true,
+      type: "object",
+      properties: {
+        localeService: {
+          required: true,
+          type: "object",
+          properties: {
+            requested: {
+              required: true,
+              type: "array",
+            },
+            available: {
+              required: true,
+              type: "array",
+            },
+            supported: {
+              required: true,
+              type: "array",
+            },
+            regionalPrefs: {
+              required: true,
+              type: "array",
+            },
+            defaultLocale: {
+              required: true,
+              type: "string",
+            },
+          },
+        },
+        osPrefs: {
+          required: true,
+          type: "object",
+          properties: {
+            systemLocales: {
+              required: true,
+              type: "array",
+            },
+            regionalPrefsLocales: {
+              required: true,
+              type: "array",
+            },
+          },
+        },
+      },
+    },
+    remoteAgent: {
+      type: "object",
+      properties: {
+        running: {
+          required: true,
+          type: "boolean",
+        },
+        url: {
+          required: true,
+          type: "string",
+        },
+      },
+    },
+    normandy: {
+      type: "object",
+      required: AppConstants.MOZ_NORMANDY,
+      properties: {
+        addonStudies: {
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              userFacingName: { type: "string", required: true },
+              branch: { type: "string", required: true },
+            },
+          },
+          required: true,
+        },
+        prefRollouts: {
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              slug: { type: "string", required: true },
+              state: { type: "string", required: true },
+            },
+          },
+          required: true,
+        },
+        prefStudies: {
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              userFacingName: { type: "string", required: true },
+              branch: { type: "string", required: true },
+            },
+          },
+          required: true,
+        },
+        nimbusExperiments: {
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              userFacingName: { type: "string", required: true },
+              branch: {
+                type: "object",
+                properties: {
+                  slug: { type: "string", required: true },
+                },
+              },
+            },
+          },
+          required: true,
+        },
+        nimbusRollouts: {
+          type: "array",
+          items: {
+            type: "object",
+            properties: {
+              featureId: { type: "string", required: true },
+              slug: { type: "string", required: true },
+            },
+          },
+        },
+      },
+    },
+  },
+};
+
+/**
+ * Throws an Error if obj doesn't conform to schema.  That way you get a nice
+ * error message and a stack to help you figure out what went wrong, which you
+ * wouldn't get if this just returned true or false instead.  There's still
+ * room for improvement in communicating validation failures, however.
+ *
+ * @param obj    The object to validate.
+ * @param schema The schema that obj should conform to.
+ */
+function validateObject(obj, schema) {
+  if (obj === undefined && !schema.required) {
+    return;
+  }
+  if (typeof schema.type != "string") {
+    throw schemaErr("'type' must be a string", schema);
+  }
+  if (objType(obj) != schema.type) {
+    throw validationErr("Object is not of the expected type", obj, schema);
+  }
+  let validatorFnName = "validateObject_" + schema.type;
+  if (!(validatorFnName in this)) {
+    throw schemaErr("Validator function not defined for type", schema);
+  }
+  this[validatorFnName](obj, schema);
+}
+
+function validateObject_object(obj, schema) {
+  if (typeof schema.properties != "object") {
+    // Don't care what obj's properties are.
+    return;
+  }
+  // First check that all the schema's properties match the object.
+  for (let prop in schema.properties) {
+    validateObject(obj[prop], schema.properties[prop]);
+  }
+  // Now check that the object doesn't have any properties not in the schema.
+  for (let prop in obj) {
+    if (!(prop in schema.properties)) {
+      throw validationErr(
+        "Object has property " + prop + " not in schema",
+        obj,
+        schema
+      );
+    }
+  }
+}
+
+function validateObject_array(array, schema) {
+  if (typeof schema.items != "object") {
+    // Don't care what the array's elements are.
+    return;
+  }
+  array.forEach(elt => validateObject(elt, schema.items));
+}
+
+function validateObject_string(str, schema) {}
+function validateObject_boolean(bool, schema) {}
+function validateObject_number(num, schema) {}
+
+function validationErr(msg, obj, schema) {
+  return new Error(
+    "Validation error: " +
+      msg +
+      ": object=" +
+      JSON.stringify(obj) +
+      ", schema=" +
+      JSON.stringify(schema)
+  );
+}
+
+function schemaErr(msg, schema) {
+  return new Error("Schema error: " + msg + ": " + JSON.stringify(schema));
+}
+
+function objType(obj) {
+  let type = typeof obj;
+  if (type != "object") {
+    return type;
+  }
+  if (Array.isArray(obj)) {
+    return "array";
+  }
+  if (obj === null) {
+    return "null";
+  }
+  return type;
+}
diff --git a/toolkit/modules/tests/browser/browser_web_channel.js b/toolkit/modules/tests/browser/browser_web_channel.js
new file mode 100644
index 0000000000..9dfa59485b
--- /dev/null
+++ b/toolkit/modules/tests/browser/browser_web_channel.js
@@ -0,0 +1,587 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+ChromeUtils.defineESModuleGetters(this, {
+  WebChannel: "resource://gre/modules/WebChannel.sys.mjs",
+});
+
+const HTTP_PATH = "http://example.com";
+const HTTP_ENDPOINT =
+  getRootDirectory(gTestPath).replace("chrome://mochitests/content", "") +
+  "file_web_channel.html";
+const HTTP_MISMATCH_PATH = "http://example.org";
+const HTTP_IFRAME_PATH = "http://mochi.test:8888";
+const HTTP_REDIRECTED_IFRAME_PATH = "http://example.org";
+
+requestLongerTimeout(2); // timeouts in debug builds.
+
+// Keep this synced with /mobile/android/tests/browser/robocop/testWebChannel.js
+// as much as possible.  (We only have that since we can't run browser chrome
+// tests on Android.  Yet?)
+var gTests = [
+  {
+    desc: "WebChannel generic message",
+    run() {
+      return new Promise(function (resolve, reject) {
+        let tab;
+        let channel = new WebChannel("generic", Services.io.newURI(HTTP_PATH));
+        channel.listen(function (id, message, target) {
+          is(id, "generic");
+          is(message.something.nested, "hello");
+          channel.stopListening();
+          gBrowser.removeTab(tab);
+          resolve();
+        });
+
+        tab = BrowserTestUtils.addTab(
+          gBrowser,
+          HTTP_PATH + HTTP_ENDPOINT + "?generic"
+        );
+      });
+    },
+  },
+  {
+    desc: "WebChannel generic message in a private window.",
+    async run() {
+      let promiseTestDone = new Promise(function (resolve, reject) {
+        let channel = new WebChannel("generic", Services.io.newURI(HTTP_PATH));
+        channel.listen(function (id, message, target) {
+          is(id, "generic");
+          is(message.something.nested, "hello");
+          channel.stopListening();
+          resolve();
+        });
+      });
+
+      const url = HTTP_PATH + HTTP_ENDPOINT + "?generic";
+      let privateWindow = await BrowserTestUtils.openNewBrowserWindow({
+        private: true,
+      });
+      await BrowserTestUtils.openNewForegroundTab(privateWindow.gBrowser, url);
+      await promiseTestDone;
+      await BrowserTestUtils.closeWindow(privateWindow);
+    },
+  },
+  {
+    desc: "WebChannel two way communication",
+    run() {
+      return new Promise(function (resolve, reject) {
+        let tab;
+        let channel = new WebChannel("twoway", Services.io.newURI(HTTP_PATH));
+
+        channel.listen(function (id, message, sender) {
+          is(id, "twoway", "bad id");
+          ok(message.command, "command not ok");
+
+          if (message.command === "one") {
+            channel.send({ data: { nested: true } }, sender);
+          }
+
+          if (message.command === "two") {
+            is(message.detail.data.nested, true);
+            channel.stopListening();
+            gBrowser.removeTab(tab);
+            resolve();
+          }
+        });
+
+        tab = BrowserTestUtils.addTab(
+          gBrowser,
+          HTTP_PATH + HTTP_ENDPOINT + "?twoway"
+        );
+      });
+    },
+  },
+  {
+    desc: "WebChannel two way communication in an iframe",
+    async run() {
+      let parentChannel = new WebChannel("echo", Services.io.newURI(HTTP_PATH));
+      let iframeChannel = new WebChannel(
+        "twoway",
+        Services.io.newURI(HTTP_IFRAME_PATH)
+      );
+      let promiseTestDone = new Promise(function (resolve, reject) {
+        parentChannel.listen(function (id, message, sender) {
+          reject(new Error("WebChannel message incorrectly sent to parent"));
+        });
+
+        iframeChannel.listen(function (id, message, sender) {
+          is(id, "twoway", "bad id (2)");
+          ok(message.command, "command not ok (2)");
+
+          if (message.command === "one") {
+            iframeChannel.send({ data: { nested: true } }, sender);
+          }
+
+          if (message.command === "two") {
+            is(message.detail.data.nested, true);
+            resolve();
+          }
+        });
+      });
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?iframe",
+        },
+        async function () {
+          await promiseTestDone;
+          parentChannel.stopListening();
+          iframeChannel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel response to a redirected iframe",
+    async run() {
+      /**
+       * This test checks that WebChannel responses are only sent
+       * to an iframe if the iframe has not redirected to another origin.
+       * Test flow:
+       * 1. create a page, embed an iframe on origin A.
+       * 2. the iframe sends a message `redirecting`, then redirects to
+       *    origin B.
+       * 3. the iframe at origin B is set up to echo any messages back to the
+       *    test parent.
+       * 4. the test parent receives the `redirecting` message from origin A.
+       *    the test parent creates a new channel with origin B.
+       * 5. when origin B is ready, it sends a `loaded` message to the test
+       *    parent, letting the test parent know origin B is ready to echo
+       *    messages.
+       * 5. the test parent tries to send a response to origin A. If the
+       *    WebChannel does not perform a valid origin check, the response
+       *    will be received by origin B. If the WebChannel does perform
+       *    a valid origin check, the response will not be sent.
+       * 6. the test parent sends a `done` message to origin B, which origin
+       *    B echoes back. If the response to origin A is not echoed but
+       *    the message to origin B is, then hooray, the test passes.
+       */
+
+      let preRedirectChannel = new WebChannel(
+        "pre_redirect",
+        Services.io.newURI(HTTP_IFRAME_PATH)
+      );
+      let postRedirectChannel = new WebChannel(
+        "post_redirect",
+        Services.io.newURI(HTTP_REDIRECTED_IFRAME_PATH)
+      );
+
+      let promiseTestDone = new Promise(function (resolve, reject) {
+        preRedirectChannel.listen(function (id, message, preRedirectSender) {
+          if (message.command === "redirecting") {
+            postRedirectChannel.listen(function (
+              aId,
+              aMessage,
+              aPostRedirectSender
+            ) {
+              is(aId, "post_redirect");
+              isnot(aMessage.command, "no_response_expected");
+
+              if (aMessage.command === "loaded") {
+                // The message should not be received on the preRedirectChannel
+                // because the target window has redirected.
+                preRedirectChannel.send(
+                  { command: "no_response_expected" },
+                  preRedirectSender
+                );
+                postRedirectChannel.send(
+                  { command: "done" },
+                  aPostRedirectSender
+                );
+              } else if (aMessage.command === "done") {
+                resolve();
+              } else {
+                reject(new Error(`Unexpected command ${aMessage.command}`));
+              }
+            });
+          } else {
+            reject(new Error(`Unexpected command ${message.command}`));
+          }
+        });
+      });
+
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?iframe_pre_redirect",
+        },
+        async function () {
+          await promiseTestDone;
+          preRedirectChannel.stopListening();
+          postRedirectChannel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel multichannel",
+    run() {
+      return new Promise(function (resolve, reject) {
+        let tab;
+        let channel = new WebChannel(
+          "multichannel",
+          Services.io.newURI(HTTP_PATH)
+        );
+
+        channel.listen(function (id, message, sender) {
+          is(id, "multichannel");
+          gBrowser.removeTab(tab);
+          resolve();
+        });
+
+        tab = BrowserTestUtils.addTab(
+          gBrowser,
+          HTTP_PATH + HTTP_ENDPOINT + "?multichannel"
+        );
+      });
+    },
+  },
+  {
+    desc: "WebChannel unsolicited send, using system principal",
+    async run() {
+      let channel = new WebChannel("echo", Services.io.newURI(HTTP_PATH));
+
+      // an unsolicted message is sent from Chrome->Content which is then
+      // echoed back. If the echo is received here, then the content
+      // received the message.
+      let messagePromise = new Promise(function (resolve, reject) {
+        channel.listen(function (id, message, sender) {
+          is(id, "echo");
+          is(message.command, "unsolicited");
+
+          resolve();
+        });
+      });
+
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?unsolicited",
+        },
+        async function (targetBrowser) {
+          channel.send(
+            { command: "unsolicited" },
+            {
+              browsingContext: targetBrowser.browsingContext,
+              principal: Services.scriptSecurityManager.getSystemPrincipal(),
+            }
+          );
+          await messagePromise;
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel unsolicited send, using target origin's principal",
+    async run() {
+      let targetURI = Services.io.newURI(HTTP_PATH);
+      let channel = new WebChannel("echo", targetURI);
+
+      // an unsolicted message is sent from Chrome->Content which is then
+      // echoed back. If the echo is received here, then the content
+      // received the message.
+      let messagePromise = new Promise(function (resolve, reject) {
+        channel.listen(function (id, message, sender) {
+          is(id, "echo");
+          is(message.command, "unsolicited");
+
+          resolve();
+        });
+      });
+
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?unsolicited",
+        },
+        async function (targetBrowser) {
+          channel.send(
+            { command: "unsolicited" },
+            {
+              browsingContext: targetBrowser.browsingContext,
+              principal: Services.scriptSecurityManager.createContentPrincipal(
+                targetURI,
+                {}
+              ),
+            }
+          );
+
+          await messagePromise;
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel unsolicited send with principal mismatch",
+    async run() {
+      let targetURI = Services.io.newURI(HTTP_PATH);
+      let channel = new WebChannel("echo", targetURI);
+
+      // two unsolicited messages are sent from Chrome->Content. The first,
+      // `unsolicited_no_response_expected` is sent to the wrong principal
+      // and should not be echoed back. The second, `done`, is sent to the
+      // correct principal and should be echoed back.
+      let messagePromise = new Promise(function (resolve, reject) {
+        channel.listen(function (id, message, sender) {
+          is(id, "echo");
+
+          if (message.command === "done") {
+            resolve();
+          } else {
+            reject(new Error(`Unexpected command ${message.command}`));
+          }
+        });
+      });
+
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?unsolicited",
+        },
+        async function (targetBrowser) {
+          let mismatchURI = Services.io.newURI(HTTP_MISMATCH_PATH);
+          let mismatchPrincipal =
+            Services.scriptSecurityManager.createContentPrincipal(
+              mismatchURI,
+              {}
+            );
+
+          // send a message to the wrong principal. It should not be delivered
+          // to content, and should not be echoed back.
+          channel.send(
+            { command: "unsolicited_no_response_expected" },
+            {
+              browsingContext: targetBrowser.browsingContext,
+              principal: mismatchPrincipal,
+            }
+          );
+
+          let targetPrincipal =
+            Services.scriptSecurityManager.createContentPrincipal(
+              targetURI,
+              {}
+            );
+
+          // send the `done` message to the correct principal. It
+          // should be echoed back.
+          channel.send(
+            { command: "done" },
+            {
+              browsingContext: targetBrowser.browsingContext,
+              principal: targetPrincipal,
+            }
+          );
+
+          await messagePromise;
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel non-window target",
+    async run() {
+      /**
+       * This test ensures messages can be received from and responses
+       * sent to non-window elements.
+       *
+       * First wait for the non-window element to send a "start" message.
+       * Then send the non-window element a "done" message.
+       * The non-window element will echo the "done" message back, if it
+       * receives the message.
+       * Listen for the response. If received, good to go!
+       */
+      let channel = new WebChannel(
+        "not_a_window",
+        Services.io.newURI(HTTP_PATH)
+      );
+
+      let testDonePromise = new Promise(function (resolve, reject) {
+        channel.listen(function (id, message, sender) {
+          if (message.command === "start") {
+            channel.send({ command: "done" }, sender);
+          } else if (message.command === "done") {
+            resolve();
+          } else {
+            reject(new Error(`Unexpected command ${message.command}`));
+          }
+        });
+      });
+
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?bubbles",
+        },
+        async function () {
+          await testDonePromise;
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel disallows non-string message from non-whitelisted origin",
+    async run() {
+      /**
+       * This test ensures that non-string messages can't be sent via WebChannels.
+       * We create a page (on a non-whitelisted origin) which should send us two
+       * messages immediately. The first message has an object for it's detail,
+       * and the second has a string. We check that we only get the second
+       * message.
+       */
+      let channel = new WebChannel("objects", Services.io.newURI(HTTP_PATH));
+      let testDonePromise = new Promise((resolve, reject) => {
+        channel.listen((id, message, sender) => {
+          is(id, "objects");
+          is(message.type, "string");
+          resolve();
+        });
+      });
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?object",
+        },
+        async function () {
+          await testDonePromise;
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel allows both string and non-string message from whitelisted origin",
+    async run() {
+      /**
+       * Same process as above, but we whitelist the origin before loading the page,
+       * and expect to get *both* messages back (each exactly once).
+       */
+      let channel = new WebChannel("objects", Services.io.newURI(HTTP_PATH));
+
+      let testDonePromise = new Promise((resolve, reject) => {
+        let sawObject = false;
+        let sawString = false;
+        channel.listen((id, message, sender) => {
+          is(id, "objects");
+          if (message.type === "object") {
+            ok(!sawObject);
+            sawObject = true;
+          } else if (message.type === "string") {
+            ok(!sawString);
+            sawString = true;
+          } else {
+            reject(new Error(`Unknown message type: ${message.type}`));
+          }
+          if (sawObject && sawString) {
+            resolve();
+          }
+        });
+      });
+      const webchannelWhitelistPref = "webchannel.allowObject.urlWhitelist";
+      let origWhitelist = Services.prefs.getCharPref(webchannelWhitelistPref);
+      let newWhitelist = origWhitelist + " " + HTTP_PATH;
+      Services.prefs.setCharPref(webchannelWhitelistPref, newWhitelist);
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?object",
+        },
+        async function () {
+          await testDonePromise;
+          Services.prefs.setCharPref(webchannelWhitelistPref, origWhitelist);
+          channel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel errors handling the message are delivered back to content",
+    async run() {
+      const ERRNO_UNKNOWN_ERROR = 999; // WebChannel.sys.mjs doesn't export this.
+
+      // The channel where we purposely fail responding to a command.
+      let channel = new WebChannel("error", Services.io.newURI(HTTP_PATH));
+      // The channel where we see the response when the content sees the error
+      let echoChannel = new WebChannel("echo", Services.io.newURI(HTTP_PATH));
+
+      let testDonePromise = new Promise((resolve, reject) => {
+        // listen for the confirmation that content saw the error.
+        echoChannel.listen((id, message, sender) => {
+          is(id, "echo");
+          is(message.error, "oh no");
+          is(message.errno, ERRNO_UNKNOWN_ERROR);
+          resolve();
+        });
+
+        // listen for a message telling us to simulate an error.
+        channel.listen((id, message, sender) => {
+          is(id, "error");
+          is(message.command, "oops");
+          throw new Error("oh no");
+        });
+      });
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?error_thrown",
+        },
+        async function () {
+          await testDonePromise;
+          channel.stopListening();
+          echoChannel.stopListening();
+        }
+      );
+    },
+  },
+  {
+    desc: "WebChannel errors due to an invalid channel are delivered back to content",
+    async run() {
+      const ERRNO_NO_SUCH_CHANNEL = 2; // WebChannel.sys.mjs doesn't export this.
+      // The channel where we see the response when the content sees the error
+      let echoChannel = new WebChannel("echo", Services.io.newURI(HTTP_PATH));
+
+      let testDonePromise = new Promise((resolve, reject) => {
+        // listen for the confirmation that content saw the error.
+        echoChannel.listen((id, message, sender) => {
+          is(id, "echo");
+          is(message.error, "No Such Channel");
+          is(message.errno, ERRNO_NO_SUCH_CHANNEL);
+          resolve();
+        });
+      });
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url: HTTP_PATH + HTTP_ENDPOINT + "?error_invalid_channel",
+        },
+        async function () {
+          await testDonePromise;
+          echoChannel.stopListening();
+        }
+      );
+    },
+  },
+]; // gTests
+
+function test() {
+  waitForExplicitFinish();
+
+  (async function () {
+    await SpecialPowers.pushPrefEnv({
+      set: [["dom.security.https_first_pbm", false]],
+    });
+
+    for (let testCase of gTests) {
+      info("Running: " + testCase.desc);
+      await testCase.run();
+    }
+  })().then(finish, ex => {
+    ok(false, "Unexpected Exception: " + ex);
+    finish();
+  });
+}
diff --git a/toolkit/modules/tests/browser/file_FinderIframeTest.html b/toolkit/modules/tests/browser/file_FinderIframeTest.html
new file mode 100644
index 0000000000..826e5dc4ca
--- /dev/null
+++ b/toolkit/modules/tests/browser/file_FinderIframeTest.html
@@ -0,0 +1,21 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+  <title>Test (i)frame offsets, bug 1366646</title>
+</head>
+<body>
+<p>top level frame</p>
+<iframe src="data:text/html,&lt;p&gt;frame without border&lt;/p&gt;
+  &lt;iframe src='data:text/html,&lt;p&gt;nested frame without border&lt;/p&gt;' height='50' width='100%' style='background-color: yellow; border: 0'&gt;&lt;/iframe&gt;
+  " style="background-color: pink; border: 0" width="100%" height="150"></iframe>
+<iframe src="data:text/html,&lt;p&gt;frame with 5px border&lt;/p&gt;
+  &lt;iframe src='data:text/html,&lt;p&gt;nested frame with 5px border&lt;/p&gt;' height='50' width='100%' style='background-color: yellow; border: solid 5px black'&gt;&lt;/iframe&gt;
+  " style="background-color: pink; border: solid 5px black" width="100%" height="150"></iframe>
+<iframe src="data:text/html,&lt;p&gt;frame with 5px padding&lt;/p&gt;
+  &lt;iframe src='data:text/html,&lt;p&gt;nested frame with 5px padding&lt;/p&gt;' height='50' width='100%' style='background-color: yellow; border: 0; padding: 5px'&gt;&lt;/iframe&gt;
+  " style="background-color: pink; border: 0; padding: 5px" width="100%" height="150"></iframe>
+<!-- Testing deprecated HTML4 iframe properties too: -->
+<iframe src="data:text/html,&lt;p&gt;frame with frameborder, marginwidth/ height and 5px padding&lt;/p&gt;
+  &lt;iframe src='data:text/html,&lt;p&gt;nested frame with frameborder, marginwidth/ height&lt;/p&gt;' height='50' width='100%' frameborder='1' marginheight='5' marginwidth='5' style='background-color: yellow;'&gt;&lt;/iframe&gt;
+  " frameborder="1" marginheight="5" marginwidth="5" style="background-color: pink; padding: 5px" width="100%" height="150"></iframe>
+</body></html>
diff --git a/toolkit/modules/tests/browser/file_FinderSample.html b/toolkit/modules/tests/browser/file_FinderSample.html
new file mode 100644
index 0000000000..e952d1fe97
--- /dev/null
+++ b/toolkit/modules/tests/browser/file_FinderSample.html
@@ -0,0 +1,824 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Childe Roland</title>
+</head>
+<body>
+<h1>"Childe Roland to the Dark Tower Came"</h1><h5>Robert Browning</h5>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>I.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>My first thought was, he lied in every word,
+<dl>
+<dd>That hoary cripple, with malicious eye</dd>
+<dd>Askance to watch the working of his lie</dd>
+</dl>
+</dd>
+<dd>On mine, and mouth scarce able to afford</dd>
+<dd>Suppression of the glee that pursed and scored
+<dl>
+<dd>Its edge, at one more victim gained thereby.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>II.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>What else should he be set for, with his staff?
+<dl>
+<dd>What, save to waylay with his lies, ensnare</dd>
+<dd>All travellers who might find him posted there,</dd>
+</dl>
+</dd>
+<dd>And ask the road? I guessed what skull-like laugh</dd>
+<dd>Would break, what crutch 'gin write my epitaph
+<dl>
+<dd>For pastime in the dusty thoroughfare,</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>III.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>If at his counsel I should turn aside
+<dl>
+<dd>Into that ominous tract which, all agree,</dd>
+<dd>Hides the Dark Tower. Yet acquiescingly</dd>
+</dl>
+</dd>
+<dd>I did turn as he pointed: neither pride</dd>
+<dd>Nor hope rekindling at the end descried,
+<dl>
+<dd>So much as gladness that some end might be.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>IV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>For, what with my whole world-wide wandering,
+<dl>
+<dd>What with my search drawn out thro' years, my hope</dd>
+<dd>Dwindled into a ghost not fit to cope</dd>
+</dl>
+</dd>
+<dd>With that obstreperous joy success would bring,</dd>
+<dd>I hardly tried now to rebuke the spring
+<dl>
+<dd>My heart made, finding failure in its scope.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>V.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>As when a sick man very near to death
+<dl>
+<dd>Seems dead indeed, and feels begin and end</dd>
+<dd>The tears and takes the farewell of each friend,</dd>
+</dl>
+</dd>
+<dd>And hears one bid the other go, draw breath</dd>
+<dd>Freelier outside ("since all is o'er," he saith,
+<dl>
+<dd>"And the blow fallen no grieving can amend;")</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>VI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>While some discuss if near the other graves
+<dl>
+<dd>Be room enough for this, and when a day</dd>
+<dd>Suits best for carrying the corpse away,</dd>
+</dl>
+</dd>
+<dd>With care about the banners, scarves and staves:</dd>
+<dd>And still the man hears all, and only craves
+<dl>
+<dd>He may not shame such tender love and stay.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>VII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Thus, I had so long suffered in this quest,
+<dl>
+<dd>Heard failure prophesied so oft, been writ</dd>
+<dd>So many times among "The Band" - to wit,</dd>
+</dl>
+</dd>
+<dd>The knights who to the Dark Tower's search addressed</dd>
+<dd>Their steps - that just to fail as they, seemed best,
+<dl>
+<dd>And all the doubt was now—should I be fit?</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>VIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>So, quiet as despair, I turned from him,
+<dl>
+<dd>That hateful cripple, out of his highway</dd>
+<dd>Into the path he pointed. All the day</dd>
+</dl>
+</dd>
+<dd>Had been a dreary one at best, and dim</dd>
+<dd>Was settling to its close, yet shot one grim
+<dl>
+<dd>Red leer to see the plain catch its estray.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>IX.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>For mark! no sooner was I fairly found
+<dl>
+<dd>Pledged to the plain, after a pace or two,</dd>
+<dd>Than, pausing to throw backward a last view</dd>
+</dl>
+</dd>
+<dd>O'er the safe road, 'twas gone; grey plain all round:</dd>
+<dd>Nothing but plain to the horizon's bound.
+<dl>
+<dd>I might go on; nought else remained to do.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>X.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>So, on I went. I think I never saw
+<dl>
+<dd>Such starved ignoble nature; nothing throve:</dd>
+<dd>For flowers - as well expect a cedar grove!</dd>
+</dl>
+</dd>
+<dd>But cockle, spurge, according to their law</dd>
+<dd>Might propagate their kind, with none to awe,
+<dl>
+<dd>You'd think; a burr had been a treasure trove.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>No! penury, inertness and grimace,
+<dl>
+<dd>In some strange sort, were the land's portion. "See</dd>
+<dd>Or shut your eyes," said Nature peevishly,</dd>
+</dl>
+</dd>
+<dd>"It nothing skills: I cannot help my case:</dd>
+<dd>'Tis the Last Judgment's fire must cure this place,
+<dl>
+<dd>Calcine its clods and set my prisoners free."</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>If there pushed any ragged thistle-stalk
+<dl>
+<dd>Above its mates, the head was chopped; the bents</dd>
+<dd>Were jealous else. What made those holes and rents</dd>
+</dl>
+</dd>
+<dd>In the dock's harsh swarth leaves, bruised as to baulk</dd>
+<dd>All hope of greenness? 'tis a brute must walk
+<dl>
+<dd>Pashing their life out, with a brute's intents.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>As for the grass, it grew as scant as hair
+<dl>
+<dd>In leprosy; thin dry blades pricked the mud</dd>
+<dd>Which underneath looked kneaded up with blood.</dd>
+</dl>
+</dd>
+<dd>One stiff blind horse, his every bone a-stare,</dd>
+<dd>Stood stupefied, however he came there:
+<dl>
+<dd>Thrust out past service from the devil's stud!</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XIV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Alive? he might be dead for aught I know,
+<dl>
+<dd>With that red gaunt and colloped neck a-strain,</dd>
+<dd>And shut eyes underneath the rusty mane;</dd>
+</dl>
+</dd>
+<dd>Seldom went such grotesqueness with such woe;</dd>
+<dd>I never saw a brute I hated so;
+<dl>
+<dd>He must be wicked to deserve such pain.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>I shut my eyes and turned them on my heart.
+<dl>
+<dd>As a man calls for wine before he fights,</dd>
+<dd>I asked one draught of earlier, happier sights,</dd>
+</dl>
+</dd>
+<dd>Ere fitly I could hope to play my part.</dd>
+<dd>Think first, fight afterwards - the soldier's art:
+<dl>
+<dd>One taste of the old time sets all to rights.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XVI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Not it! I fancied Cuthbert's reddening face
+<dl>
+<dd>Beneath its garniture of curly gold,</dd>
+<dd>Dear fellow, till I almost felt him fold</dd>
+</dl>
+</dd>
+<dd>An arm in mine to fix me to the place</dd>
+<dd>That way he used. Alas, one night's disgrace!
+<dl>
+<dd>Out went my heart's new fire and left it cold.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XVII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Giles then, the soul of honour - there he stands
+<dl>
+<dd>Frank as ten years ago when knighted first.</dd>
+<dd>What honest men should dare (he said) he durst.</dd>
+</dl>
+</dd>
+<dd>Good - but the scene shifts - faugh! what hangman hands</dd>
+<dd>Pin to his breast a parchment? His own bands
+<dl>
+<dd>Read it. Poor traitor, spit upon and curst!</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XVIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Better this present than a past like that;
+<dl>
+<dd>Back therefore to my darkening path again!</dd>
+<dd>No sound, no sight as far as eye could strain.</dd>
+</dl>
+</dd>
+<dd>Will the night send a howlet or a bat?</dd>
+<dd>I asked: when something on the dismal flat
+<dl>
+<dd>Came to arrest my thoughts and change their train.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XIX.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>A sudden little river crossed my path
+<dl>
+<dd>As unexpected as a serpent comes.</dd>
+<dd>No sluggish tide congenial to the glooms;</dd>
+</dl>
+</dd>
+<dd>This, as it frothed by, might have been a bath</dd>
+<dd>For the fiend's glowing hoof - to see the wrath
+<dl>
+<dd>Of its black eddy bespate with flakes and spumes.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XX.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>So petty yet so spiteful! All along
+<dl>
+<dd>Low scrubby alders kneeled down over it;</dd>
+<dd>Drenched willows flung them headlong in a fit</dd>
+</dl>
+</dd>
+<dd>Of mute despair, a suicidal throng:</dd>
+<dd>The river which had done them all the wrong,
+<dl>
+<dd>Whate'er that was, rolled by, deterred no whit.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Which, while I forded, - good saints, how I feared
+<dl>
+<dd>To set my foot upon a dead man's cheek,</dd>
+<dd>Each step, or feel the spear I thrust to seek</dd>
+</dl>
+</dd>
+<dd>For hollows, tangled in his hair or beard!</dd>
+<dd>—It may have been a water-rat I speared,
+<dl>
+<dd>But, ugh! it sounded like a baby's shriek.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Glad was I when I reached the other bank.
+<dl>
+<dd>Now for a better country. Vain presage!</dd>
+<dd>Who were the strugglers, what war did they wage,</dd>
+</dl>
+</dd>
+<dd>Whose savage trample thus could pad the dank</dd>
+<dd>Soil to a plash? Toads in a poisoned tank,
+<dl>
+<dd>Or wild cats in a red-hot iron cage—</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>The fight must so have seemed in that fell cirque.
+<dl>
+<dd>What penned them there, with all the plain to choose?</dd>
+<dd>No foot-print leading to that horrid mews,</dd>
+</dl>
+</dd>
+<dd>None out of it. Mad brewage set to work</dd>
+<dd>Their brains, no doubt, like galley-slaves the Turk
+<dl>
+<dd>Pits for his pastime, Christians against Jews.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXIV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>And more than that - a furlong on - why, there!
+<dl>
+<dd>What bad use was that engine for, that wheel,</dd>
+<dd>Or brake, not wheel - that harrow fit to reel</dd>
+</dl>
+</dd>
+<dd>Men's bodies out like silk? with all the air</dd>
+<dd>Of Tophet's tool, on earth left unaware,
+<dl>
+<dd>Or brought to sharpen its rusty teeth of steel.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Then came a bit of stubbed ground, once a wood,
+<dl>
+<dd>Next a marsh, it would seem, and now mere earth</dd>
+<dd>Desperate and done with; (so a fool finds mirth,</dd>
+</dl>
+</dd>
+<dd>Makes a thing and then mars it, till his mood</dd>
+<dd>Changes and off he goes!) within a rood—
+<dl>
+<dd>Bog, clay and rubble, sand and stark black dearth.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXVI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Now blotches rankling, coloured gay and grim,
+<dl>
+<dd>Now patches where some leanness of the soil's</dd>
+<dd>Broke into moss or substances like boils;</dd>
+</dl>
+</dd>
+<dd>Then came some palsied oak, a cleft in him</dd>
+<dd>Like a distorted mouth that splits its rim
+<dl>
+<dd>Gaping at death, and dies while it recoils.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXVII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>And just as far as ever from the end!
+<dl>
+<dd>Nought in the distance but the evening, nought</dd>
+<dd>To point my footstep further! At the thought,</dd>
+</dl>
+</dd>
+<dd>A great black bird, Apollyon's bosom-friend,</dd>
+<dd>Sailed past, nor beat his wide wing dragon-penned
+<dl>
+<dd>That brushed my cap—perchance the guide I sought.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXVIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>For, looking up, aware I somehow grew,
+<dl>
+<dd>'Spite of the dusk, the plain had given place</dd>
+<dd>All round to mountains - with such name to grace</dd>
+</dl>
+</dd>
+<dd>Mere ugly heights and heaps now stolen in view.</dd>
+<dd>How thus they had surprised me, - solve it, you!
+<dl>
+<dd>How to get from them was no clearer case.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXIX.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Yet half I seemed to recognise some trick
+<dl>
+<dd>Of mischief happened to me, God knows when—</dd>
+<dd>In a bad dream perhaps. Here ended, then,</dd>
+</dl>
+</dd>
+<dd>Progress this way. When, in the very nick</dd>
+<dd>Of giving up, one time more, came a click
+<dl>
+<dd>As when a trap shuts - you're inside the den!</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXX.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Burningly it came on me all at once,
+<dl>
+<dd>This was the place! those two hills on the right,</dd>
+<dd>Crouched like two bulls locked horn in horn in fight;</dd>
+</dl>
+</dd>
+<dd>While to the left, a tall scalped mountain... Dunce,</dd>
+<dd>Dotard, a-dozing at the very nonce,
+<dl>
+<dd>After a life spent training for the sight!</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXXI.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>What in the midst lay but the Tower itself?
+<dl>
+<dd>The round squat turret, blind as the fool's heart</dd>
+<dd>Built of brown stone, without a counterpart</dd>
+</dl>
+</dd>
+<dd>In the whole world. The tempest's mocking elf</dd>
+<dd>Points to the shipman thus the unseen shelf
+<dl>
+<dd>He strikes on, only when the timbers start.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXXII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Not see? because of night perhaps? - why, day
+<dl>
+<dd>Came back again for that! before it left,</dd>
+<dd>The dying sunset kindled through a cleft:</dd>
+</dl>
+</dd>
+<dd>The hills, like giants at a hunting, lay</dd>
+<dd>Chin upon hand, to see the game at bay,—
+<dl>
+<dd>"Now stab and end the creature - to the heft!"</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXXIII.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>Not hear? when noise was everywhere! it tolled
+<dl>
+<dd>Increasing like a bell. Names in my ears</dd>
+<dd>Of all the lost adventurers my peers,—</dd>
+</dl>
+</dd>
+<dd>How such a one was strong, and such was bold,</dd>
+<dd>And such was fortunate, yet each of old
+<dl>
+<dd>Lost, lost! one moment knelled the woe of years.</dd>
+</dl>
+</dd>
+</dl>
+<p><br /></p>
+<dl>
+<dd>
+<dl>
+<dd>
+<dl>
+<dd>XXXIV.</dd>
+</dl>
+</dd>
+</dl>
+</dd>
+<dd>There they stood, ranged along the hillsides, met
+<dl>
+<dd>To view the last of me, a living frame</dd>
+<dd>For one more picture! in a sheet of flame</dd>
+</dl>
+</dd>
+<dd>I saw them and I knew them all. And yet</dd>
+<dd>Dauntless the slug-horn to my lips I set,
+<dl>
+<dd>And blew "<i>Childe Roland to the Dark Tower came.</i>"</dd>
+</dl>
+</dd>
+</dl>
+</body>
+</html>
diff --git a/toolkit/modules/tests/browser/file_getSelectionDetails_inputs.html b/toolkit/modules/tests/browser/file_getSelectionDetails_inputs.html
new file mode 100644
index 0000000000..2e49146785
--- /dev/null
+++ b/toolkit/modules/tests/browser/file_getSelectionDetails_inputs.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <input id="url-no-scheme" value="test.example.com" >
+    <input id="url-with-scheme" value="https://test.example.com">
+    <input id="not-url" value="foo. bar">
+    <input id="not-url-number" value="3.5">
+  </body>
+</html>
diff --git a/toolkit/modules/tests/browser/file_web_channel.html b/toolkit/modules/tests/browser/file_web_channel.html
new file mode 100644
index 0000000000..bcc9a13da0
--- /dev/null
+++ b/toolkit/modules/tests/browser/file_web_channel.html
@@ -0,0 +1,235 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>web_channel_test</title>
+</head>
+<body>
+<script>
+   var IFRAME_SRC_ROOT =
+     "http://mochi.test:8888" +
+     location.pathname.replace("web_channel.html", "web_channel_iframe.html");
+
+  window.onload = function() {
+    var testName = window.location.search.replace(/^\?/, "");
+
+    switch (testName) {
+      case "generic":
+        test_generic();
+        break;
+      case "twoway":
+        test_twoWay();
+        break;
+      case "multichannel":
+        test_multichannel();
+        break;
+      case "iframe":
+        test_iframe();
+        break;
+      case "iframe_pre_redirect":
+        test_iframe_pre_redirect();
+        break;
+      case "unsolicited":
+        test_unsolicited();
+        break;
+      case "bubbles":
+        test_bubbles();
+        break;
+      case "object":
+        test_object();
+        break;
+      case "error_thrown":
+        test_error_thrown();
+        break;
+      case "error_invalid_channel":
+        test_error_invalid_channel();
+        break;
+      default:
+        throw new Error(`INVALID TEST NAME ${testName}`);
+    }
+  };
+
+  function test_generic() {
+    var event = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "generic",
+        message: {
+          something: {
+            nested: "hello",
+          },
+        },
+      }),
+    });
+
+    window.dispatchEvent(event);
+  }
+
+  function test_twoWay() {
+    var firstMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "twoway",
+        message: {
+          command: "one",
+        },
+      }),
+    });
+
+    window.addEventListener("WebChannelMessageToContent", function(e) {
+      var secondMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+        detail: JSON.stringify({
+          id: "twoway",
+          message: {
+            command: "two",
+            detail: e.detail.message,
+          },
+        }),
+      });
+
+      if (!e.detail.message.error) {
+        window.dispatchEvent(secondMessage);
+      }
+    }, true);
+
+    window.dispatchEvent(firstMessage);
+  }
+
+  function test_multichannel() {
+    var event1 = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "wrongchannel",
+        message: {},
+      }),
+    });
+
+    var event2 = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "multichannel",
+        message: {},
+      }),
+    });
+
+    window.dispatchEvent(event1);
+    window.dispatchEvent(event2);
+  }
+
+  function test_iframe() {
+    // Note that this message is the response to the message sent
+    // by the iframe!  This is bad, as this page is *not* trusted.
+    window.addEventListener("WebChannelMessageToContent", function(e) {
+      // the test parent will fail if the echo message is received.
+      echoEventToChannel(e, "echo");
+    });
+
+    // only attach the iframe for the iframe test to avoid
+    // interfering with other tests.
+    var iframe = document.createElement("iframe");
+    iframe.setAttribute("src", IFRAME_SRC_ROOT + "?iframe");
+    document.body.appendChild(iframe);
+  }
+
+  function test_iframe_pre_redirect() {
+    var iframe = document.createElement("iframe");
+    iframe.setAttribute("src", IFRAME_SRC_ROOT + "?iframe_pre_redirect");
+    document.body.appendChild(iframe);
+  }
+
+  function test_unsolicited() {
+    // echo any unsolicted events back to chrome.
+    window.addEventListener("WebChannelMessageToContent", function(e) {
+      echoEventToChannel(e, "echo");
+    }, true);
+  }
+
+  function test_bubbles() {
+    var event = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "not_a_window",
+        message: {
+          command: "start",
+        },
+      }),
+    });
+
+    var nonWindowTarget = document.getElementById("not_a_window");
+
+    nonWindowTarget.addEventListener("WebChannelMessageToContent", function(e) {
+      echoEventToChannel(e, "not_a_window");
+    }, true);
+
+
+    nonWindowTarget.dispatchEvent(event);
+  }
+
+  function test_object() {
+    let objectMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: {
+        id: "objects",
+        message: { type: "object" },
+      },
+    });
+
+    let stringMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "objects",
+        message: { type: "string" },
+      }),
+    });
+    // Test fails if objectMessage is received, we send stringMessage to know
+    // when we should stop listening for objectMessage
+    window.dispatchEvent(objectMessage);
+    window.dispatchEvent(stringMessage);
+  }
+
+  function test_error_thrown() {
+   var event = new window.CustomEvent("WebChannelMessageToChrome", {
+     detail: JSON.stringify({
+       id: "error",
+       message: {
+         command: "oops",
+       },
+     }),
+   });
+
+   // echo the response back to chrome - chrome will check it is the
+   // expected error.
+   window.addEventListener("WebChannelMessageToContent", function(e) {
+     echoEventToChannel(e, "echo");
+   }, true);
+
+   window.dispatchEvent(event);
+  }
+
+  function test_error_invalid_channel() {
+   var event = new window.CustomEvent("WebChannelMessageToChrome", {
+     detail: JSON.stringify({
+       id: "invalid-channel",
+       message: {
+         command: "oops",
+       },
+     }),
+   });
+
+   // echo the response back to chrome - chrome will check it is the
+   // expected error.
+   window.addEventListener("WebChannelMessageToContent", function(e) {
+     echoEventToChannel(e, "echo");
+   }, true);
+
+   window.dispatchEvent(event);
+  }
+
+  function echoEventToChannel(e, channelId) {
+    var echoedEvent = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: channelId,
+        message: e.detail.message,
+      }),
+    });
+
+    e.target.dispatchEvent(echoedEvent);
+  }
+</script>
+
+<div id="not_a_window"></div>
+</body>
+</html>
diff --git a/toolkit/modules/tests/browser/file_web_channel_iframe.html b/toolkit/modules/tests/browser/file_web_channel_iframe.html
new file mode 100644
index 0000000000..101512184a
--- /dev/null
+++ b/toolkit/modules/tests/browser/file_web_channel_iframe.html
@@ -0,0 +1,96 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>web_channel_test (iframe)</title>
+</head>
+<body>
+<script>
+  var REDIRECTED_IFRAME_SRC_ROOT = "http://example.org/" + location.pathname;
+
+  window.onload = function() {
+    var testName = window.location.search.replace(/^\?/, "");
+    switch (testName) {
+      case "iframe":
+        test_iframe();
+        break;
+      case "iframe_pre_redirect":
+        test_iframe_pre_redirect();
+        break;
+      case "iframe_post_redirect":
+        test_iframe_post_redirect();
+        break;
+      default:
+        throw new Error(`INVALID TEST NAME ${testName}`);
+    }
+  };
+
+  function test_iframe() {
+    var firstMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "twoway",
+        message: {
+          command: "one",
+        },
+      }),
+    });
+
+    window.addEventListener("WebChannelMessageToContent", function(e) {
+      var secondMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+        detail: JSON.stringify({
+          id: "twoway",
+          message: {
+            command: "two",
+            detail: e.detail.message,
+          },
+        }),
+      });
+
+      if (!e.detail.message.error) {
+        window.dispatchEvent(secondMessage);
+      }
+    }, true);
+
+    window.dispatchEvent(firstMessage);
+  }
+
+
+  function test_iframe_pre_redirect() {
+    var firstMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "pre_redirect",
+        message: {
+          command: "redirecting",
+        },
+      }),
+    });
+    window.dispatchEvent(firstMessage);
+    document.location = REDIRECTED_IFRAME_SRC_ROOT + "?iframe_post_redirect";
+  }
+
+  function test_iframe_post_redirect() {
+    window.addEventListener("WebChannelMessageToContent", function(e) {
+      var echoMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+        detail: JSON.stringify({
+          id: "post_redirect",
+          message: e.detail.message,
+        }),
+      });
+
+      window.dispatchEvent(echoMessage);
+    }, true);
+
+    // Let the test parent know the page has loaded and is ready to echo events
+    var loadedMessage = new window.CustomEvent("WebChannelMessageToChrome", {
+      detail: JSON.stringify({
+        id: "post_redirect",
+        message: {
+          command: "loaded",
+        },
+      }),
+    });
+    window.dispatchEvent(loadedMessage);
+  }
+</script>
+</body>
+</html>
diff --git a/toolkit/modules/tests/browser/head.js b/toolkit/modules/tests/browser/head.js
new file mode 100644
index 0000000000..7c3f75b106
--- /dev/null
+++ b/toolkit/modules/tests/browser/head.js
@@ -0,0 +1,251 @@
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+});
+
+const kFixtureBaseURL =
+  "https://example.com/browser/toolkit/modules/tests/browser/";
+
+function removeDupes(list) {
+  let j = 0;
+  for (let i = 1; i < list.length; i++) {
+    if (list[i] != list[j]) {
+      j++;
+      if (i != j) {
+        list[j] = list[i];
+      }
+    }
+  }
+  list.length = j + 1;
+}
+
+function compareLists(list1, list2, kind) {
+  list1.sort();
+  removeDupes(list1);
+  list2.sort();
+  removeDupes(list2);
+  is(String(list1), String(list2), `${kind} URLs correct`);
+}
+
+async function promiseOpenFindbar(findbar) {
+  await gBrowser.getFindBar();
+  findbar.onFindCommand();
+  return gFindBar._startFindDeferred && gFindBar._startFindDeferred.promise;
+}
+
+function promiseFindResult(findbar, str = null) {
+  let highlightFinished = false;
+  let findFinished = false;
+  return new Promise(resolve => {
+    let listener = {
+      onFindResult({ searchString }) {
+        if (str !== null && str != searchString) {
+          return;
+        }
+        findFinished = true;
+        if (highlightFinished) {
+          findbar.browser.finder.removeResultListener(listener);
+          resolve();
+        }
+      },
+      onHighlightFinished() {
+        highlightFinished = true;
+        if (findFinished) {
+          findbar.browser.finder.removeResultListener(listener);
+          resolve();
+        }
+      },
+      onMatchesCountResult: () => {},
+    };
+    findbar.browser.finder.addResultListener(listener);
+  });
+}
+
+function promiseEnterStringIntoFindField(findbar, str) {
+  let promise = promiseFindResult(findbar, str);
+  for (let i = 0; i < str.length; i++) {
+    let event = new KeyboardEvent("keypress", {
+      bubbles: true,
+      cancelable: true,
+      view: null,
+      keyCode: 0,
+      charCode: str.charCodeAt(i),
+    });
+    findbar._findField.dispatchEvent(event);
+  }
+  return promise;
+}
+
+function promiseTestHighlighterOutput(
+  browser,
+  word,
+  expectedResult,
+  extraTest = () => {}
+) {
+  return SpecialPowers.spawn(
+    browser,
+    [{ word, expectedResult, extraTest: extraTest.toSource() }],
+    async function ({ word, expectedResult, extraTest }) {
+      return new Promise((resolve, reject) => {
+        let stubbed = {};
+        let callCounts = {
+          insertCalls: [],
+          removeCalls: [],
+          animationCalls: [],
+        };
+        let lastMaskNode, lastOutlineNode;
+        let rects = [];
+
+        // Amount of milliseconds to wait after the last time one of our stubs
+        // was called.
+        const kTimeoutMs = 1000;
+        // The initial timeout may wait for a while for results to come in.
+        let timeout = content.setTimeout(
+          () => finish(false, "Timeout"),
+          kTimeoutMs * 5
+        );
+
+        function finish(ok = true, message = "finished with error") {
+          // Restore the functions we stubbed out.
+          try {
+            content.document.insertAnonymousContent = stubbed.insert;
+            content.document.removeAnonymousContent = stubbed.remove;
+          } catch (ex) {}
+          stubbed = {};
+          content.clearTimeout(timeout);
+
+          if (expectedResult.rectCount !== 0) {
+            Assert.ok(ok, message);
+          }
+
+          Assert.greaterOrEqual(
+            callCounts.insertCalls.length,
+            expectedResult.insertCalls[0],
+            `Min. insert calls should match for '${word}'.`
+          );
+          Assert.lessOrEqual(
+            callCounts.insertCalls.length,
+            expectedResult.insertCalls[1],
+            `Max. insert calls should match for '${word}'.`
+          );
+          Assert.greaterOrEqual(
+            callCounts.removeCalls.length,
+            expectedResult.removeCalls[0],
+            `Min. remove calls should match for '${word}'.`
+          );
+          Assert.lessOrEqual(
+            callCounts.removeCalls.length,
+            expectedResult.removeCalls[1],
+            `Max. remove calls should match for '${word}'.`
+          );
+
+          // We reached the amount of calls we expected, so now we can check
+          // the amount of rects.
+          if (!lastMaskNode && expectedResult.rectCount !== 0) {
+            Assert.ok(
+              false,
+              `No mask node found, but expected ${expectedResult.rectCount} rects.`
+            );
+          }
+
+          Assert.equal(
+            rects.length,
+            expectedResult.rectCount,
+            `Amount of inserted rects should match for '${word}'.`
+          );
+
+          if ("animationCalls" in expectedResult) {
+            Assert.greaterOrEqual(
+              callCounts.animationCalls.length,
+              expectedResult.animationCalls[0],
+              `Min. animation calls should match for '${word}'.`
+            );
+            Assert.lessOrEqual(
+              callCounts.animationCalls.length,
+              expectedResult.animationCalls[1],
+              `Max. animation calls should match for '${word}'.`
+            );
+          }
+
+          // Allow more specific assertions to be tested in `extraTest`.
+          // eslint-disable-next-line no-eval
+          extraTest = eval(extraTest);
+          extraTest(lastMaskNode, lastOutlineNode, rects);
+
+          resolve();
+        }
+
+        function stubAnonymousContentNode(domNode, anonNode) {
+          let originals = [
+            anonNode.setTextContentForElement,
+            anonNode.setAttributeForElement,
+            anonNode.removeAttributeForElement,
+            anonNode.setCutoutRectsForElement,
+            anonNode.setAnimationForElement,
+          ];
+          anonNode.setTextContentForElement = (id, text) => {
+            try {
+              (domNode.querySelector("#" + id) || domNode).textContent = text;
+            } catch (ex) {}
+            return originals[0].call(anonNode, id, text);
+          };
+          anonNode.setAttributeForElement = (id, attrName, attrValue) => {
+            try {
+              (domNode.querySelector("#" + id) || domNode).setAttribute(
+                attrName,
+                attrValue
+              );
+            } catch (ex) {}
+            return originals[1].call(anonNode, id, attrName, attrValue);
+          };
+          anonNode.removeAttributeForElement = (id, attrName) => {
+            try {
+              let node = domNode.querySelector("#" + id) || domNode;
+              if (node.hasAttribute(attrName)) {
+                node.removeAttribute(attrName);
+              }
+            } catch (ex) {}
+            return originals[2].call(anonNode, id, attrName);
+          };
+          anonNode.setCutoutRectsForElement = (id, cutoutRects) => {
+            rects = cutoutRects;
+            return originals[3].call(anonNode, id, cutoutRects);
+          };
+          anonNode.setAnimationForElement = (id, keyframes, options) => {
+            callCounts.animationCalls.push([keyframes, options]);
+            return originals[4].call(anonNode, id, keyframes, options);
+          };
+        }
+
+        // Create a function that will stub the original version and collects
+        // the arguments so we can check the results later.
+        function stub(which) {
+          stubbed[which] = content.document[which + "AnonymousContent"];
+          let prop = which + "Calls";
+          return function (node) {
+            callCounts[prop].push(node);
+            if (which == "insert") {
+              if (node.outerHTML.indexOf("outlineMask") > -1) {
+                lastMaskNode = node;
+              } else {
+                lastOutlineNode = node;
+              }
+            }
+            content.clearTimeout(timeout);
+            timeout = content.setTimeout(() => {
+              finish();
+            }, kTimeoutMs);
+            let res = stubbed[which].call(content.document, node);
+            if (which == "insert") {
+              stubAnonymousContentNode(node, res);
+            }
+            return res;
+          };
+        }
+        content.document.insertAnonymousContent = stub("insert");
+        content.document.removeAnonymousContent = stub("remove");
+      });
+    }
+  );
+}