--- a/browser/base/content/test/webrtc/browser.ini
+++ b/browser/base/content/test/webrtc/browser.ini
@@ -27,14 +27,15 @@ skip-if = (os == "win" && !debug) || (os
 [browser_devices_get_user_media_screen.js]
 skip-if = (os == 'linux') # Bug 1503991
 [browser_devices_get_user_media_tear_off_tab.js]
 [browser_devices_get_user_media_unprompted_access.js]
 [browser_devices_get_user_media_unprompted_access_in_frame.js]
 [browser_devices_get_user_media_unprompted_access_tear_off_tab.js]
 skip-if = (os == "win" && bits == 64) # win8: bug 1334752
 [browser_devices_get_user_media_unprompted_access_queue_request.js]
+[browser_global_mute_toggles.js]
 [browser_notification_silencing.js]
 [browser_stop_sharing_button.js]
 [browser_stop_streams_on_indicator_close.js]
 [browser_tab_switch_warning.js]
 [browser_webrtc_hooks.js]
 [browser_devices_get_user_media_queue_request.js]

--- a/browser/base/content/test/webrtc/browser_devices_get_user_media.js
+++ b/browser/base/content/test/webrtc/browser_devices_get_user_media.js
@@ -712,16 +712,22 @@ var gTests = [
       info("request video, stop sharing resets video only");
       await stopAndCheckPerm(false, true);
     },
   },
 
   {
     desc: "test showControlCenter",
     run: async function checkShowControlCenter() {
+      if (!USING_LEGACY_INDICATOR) {
+        // The indicator only links to the control center for the
+        // legacy indicator.
+        return;
+      }
+
       let observerPromise = expectObserverCalled("getUserMedia:request");
       let promise = promisePopupNotificationShown("webRTC-shareDevices");
       await promiseRequestDevice(false, true);
       await promise;
       await observerPromise;
       checkDeviceSelectors(false, true);
 
       let indicator = promiseIndicatorWindow();
@@ -739,33 +745,28 @@ var gTests = [
         { video: true },
         "expected camera to be shared"
       );
 
       await indicator;
       await checkSharingUI({ video: true });
 
       ok(identityPopupHidden(), "control center should be hidden");
-      if (USING_LEGACY_INDICATOR && IS_MAC) {
+      if (IS_MAC) {
         let activeStreams = webrtcUI.getActiveStreams(true, false, false);
         webrtcUI.showSharingDoorhanger(activeStreams[0]);
       } else {
         let win = Services.wm.getMostRecentWindow(
           "Browser:WebRTCGlobalIndicator"
         );
 
-        // The legacy indicator uses a different button ID when sharing
-        // your camera.
-        let buttonID = USING_LEGACY_INDICATOR
-          ? "audioVideoButton"
-          : "camera-button";
-
-        let elt = win.document.getElementById(buttonID);
+        let elt = win.document.getElementById("audioVideoButton");
         EventUtils.synthesizeMouseAtCenter(elt, {}, win);
       }
+
       await TestUtils.waitForCondition(
         () => !identityPopupHidden(),
         "wait for control center to open"
       );
       ok(!identityPopupHidden(), "control center should be open");
 
       gIdentityHandler._identityPopup.hidePopup();
 

new file mode 100644
--- /dev/null
+++ b/browser/base/content/test/webrtc/browser_global_mute_toggles.js
@@ -0,0 +1,312 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content/",
+  "https://example.com/"
+);
+const TEST_PAGE = TEST_ROOT + "get_user_media.html";
+const MUTE_TOPICS = [
+  "getUserMedia:muteVideo",
+  "getUserMedia:unmuteVideo",
+  "getUserMedia:muteAudio",
+  "getUserMedia:unmuteAudio",
+];
+
+add_task(async function setup() {
+  let prefs = [
+    [PREF_PERMISSION_FAKE, true],
+    [PREF_AUDIO_LOOPBACK, ""],
+    [PREF_VIDEO_LOOPBACK, ""],
+    [PREF_FAKE_STREAMS, true],
+    [PREF_FOCUS_SOURCE, false],
+  ];
+  await SpecialPowers.pushPrefEnv({ set: prefs });
+});
+
+/**
+ * Returns a Promise that resolves when the content process for
+ * <browser> fires the right observer notification based on the
+ * value of isMuted for the camera.
+ *
+ * Note: Callers must ensure that they first call
+ * BrowserTestUtils.startObservingTopics to monitor the mute and
+ * unmute observer notifications for this to work properly.
+ *
+ * @param {<xul:browser>} browser - The browser running in the content process
+ * to be monitored.
+ * @param {Boolean} isMuted - True if the muted topic should be fired.
+ * @return {Promise}
+ * @resolves {undefined} When the notification fires.
+ */
+function waitForCameraMuteState(browser, isMuted) {
+  let topic = isMuted ? "getUserMedia:muteVideo" : "getUserMedia:unmuteVideo";
+  return BrowserTestUtils.contentTopicObserved(browser.browsingContext, topic);
+}
+
+/**
+ * Returns a Promise that resolves when the content process for
+ * <browser> fires the right observer notification based on the
+ * value of isMuted for the microphone.
+ *
+ * Note: Callers must ensure that they first call
+ * BrowserTestUtils.startObservingTopics to monitor the mute and
+ * unmute observer notifications for this to work properly.
+ *
+ * @param {<xul:browser>} browser - The browser running in the content process
+ * to be monitored.
+ * @param {Boolean} isMuted - True if the muted topic should be fired.
+ * @return {Promise}
+ * @resolves {undefined} When the notification fires.
+ */
+function waitForMicrophoneMuteState(browser, isMuted) {
+  let topic = isMuted ? "getUserMedia:muteAudio" : "getUserMedia:unmuteAudio";
+  return BrowserTestUtils.contentTopicObserved(browser.browsingContext, topic);
+}
+
+/**
+ * Tests that the global mute toggles fire the right observer
+ * notifications in pre-existing content processes.
+ */
+add_task(async function test_notifications() {
+  await BrowserTestUtils.withNewTab(TEST_PAGE, async browser => {
+    let indicatorPromise = promiseIndicatorWindow();
+
+    await shareDevices(
+      browser,
+      true /* camera */,
+      true /* microphone */,
+      false /* screen */
+    );
+
+    let indicator = await indicatorPromise;
+    let doc = indicator.document;
+
+    let microphoneMute = doc.getElementById("microphone-mute-toggle");
+    let cameraMute = doc.getElementById("camera-mute-toggle");
+
+    Assert.ok(
+      !microphoneMute.checked,
+      "Microphone toggle should not start checked."
+    );
+    Assert.ok(!cameraMute.checked, "Camera toggle should not start checked.");
+
+    await BrowserTestUtils.startObservingTopics(
+      browser.browsingContext,
+      MUTE_TOPICS
+    );
+
+    info("Muting microphone...");
+    let microphoneMuted = waitForMicrophoneMuteState(browser, true);
+    microphoneMute.click();
+    await microphoneMuted;
+    info("Microphone successfully muted.");
+
+    info("Muting camera...");
+    let cameraMuted = waitForCameraMuteState(browser, true);
+    cameraMute.click();
+    await cameraMuted;
+    info("Camera successfully muted.");
+
+    Assert.ok(
+      microphoneMute.checked,
+      "Microphone toggle should now be checked."
+    );
+    Assert.ok(cameraMute.checked, "Camera toggle should now be checked.");
+
+    info("Unmuting microphone...");
+    let microphoneUnmuted = waitForMicrophoneMuteState(browser, false);
+    microphoneMute.click();
+    await microphoneUnmuted;
+    info("Microphone successfully unmuted.");
+
+    info("Unmuting camera...");
+    let cameraUnmuted = waitForCameraMuteState(browser, false);
+    cameraMute.click();
+    await cameraUnmuted;
+    info("Camera successfully unmuted.");
+
+    await BrowserTestUtils.stopObservingTopics(
+      browser.browsingContext,
+      MUTE_TOPICS
+    );
+  });
+});
+
+/**
+ * Tests that if sharing stops while muted, and the indicator closes,
+ * then the mute state is reset.
+ */
+add_task(async function test_closing_indicator_resets_mute() {
+  await BrowserTestUtils.withNewTab(TEST_PAGE, async browser => {
+    let indicatorPromise = promiseIndicatorWindow();
+
+    await shareDevices(
+      browser,
+      true /* camera */,
+      true /* microphone */,
+      false /* screen */
+    );
+
+    let indicator = await indicatorPromise;
+    let doc = indicator.document;
+
+    let microphoneMute = doc.getElementById("microphone-mute-toggle");
+    let cameraMute = doc.getElementById("camera-mute-toggle");
+
+    Assert.ok(
+      !microphoneMute.checked,
+      "Microphone toggle should not start checked."
+    );
+    Assert.ok(!cameraMute.checked, "Camera toggle should not start checked.");
+
+    await BrowserTestUtils.startObservingTopics(
+      browser.browsingContext,
+      MUTE_TOPICS
+    );
+
+    info("Muting microphone...");
+    let microphoneMuted = waitForMicrophoneMuteState(browser, true);
+    microphoneMute.click();
+    await microphoneMuted;
+    info("Microphone successfully muted.");
+
+    info("Muting camera...");
+    let cameraMuted = waitForCameraMuteState(browser, true);
+    cameraMute.click();
+    await cameraMuted;
+    info("Camera successfully muted.");
+
+    Assert.ok(
+      microphoneMute.checked,
+      "Microphone toggle should now be checked."
+    );
+    Assert.ok(cameraMute.checked, "Camera toggle should now be checked.");
+
+    let allUnmuted = Promise.all([
+      waitForMicrophoneMuteState(browser, false),
+      waitForCameraMuteState(browser, false),
+    ]);
+
+    await closeStream();
+    await allUnmuted;
+
+    await BrowserTestUtils.stopObservingTopics(
+      browser.browsingContext,
+      MUTE_TOPICS
+    );
+  });
+});
+
+/**
+ * Test that if the global mute state is set, then newly created
+ * content processes also have their tracks muted after sending
+ * a getUserMedia request.
+ */
+add_task(async function test_new_processes() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    url: TEST_PAGE,
+  });
+  let browser1 = tab1.linkedBrowser;
+
+  let indicatorPromise = promiseIndicatorWindow();
+
+  await shareDevices(
+    browser1,
+    true /* camera */,
+    true /* microphone */,
+    false /* screen */
+  );
+
+  let indicator = await indicatorPromise;
+  let doc = indicator.document;
+
+  let microphoneMute = doc.getElementById("microphone-mute-toggle");
+  let cameraMute = doc.getElementById("camera-mute-toggle");
+
+  Assert.ok(
+    !microphoneMute.checked,
+    "Microphone toggle should not start checked."
+  );
+  Assert.ok(!cameraMute.checked, "Camera toggle should not start checked.");
+
+  await BrowserTestUtils.startObservingTopics(
+    browser1.browsingContext,
+    MUTE_TOPICS
+  );
+
+  info("Muting microphone...");
+  let microphoneMuted = waitForMicrophoneMuteState(browser1, true);
+  microphoneMute.click();
+  await microphoneMuted;
+  info("Microphone successfully muted.");
+
+  info("Muting camera...");
+  let cameraMuted = waitForCameraMuteState(browser1, true);
+  cameraMute.click();
+  await cameraMuted;
+  info("Camera successfully muted.");
+
+  // We'll make sure a new process is being launched by observing
+  // for the ipc:content-created notification.
+  let processLaunched = TestUtils.topicObserved("ipc:content-created");
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    url: TEST_PAGE,
+    forceNewProcess: true,
+  });
+  let browser2 = tab2.linkedBrowser;
+
+  await processLaunched;
+
+  await BrowserTestUtils.startObservingTopics(
+    browser2.browsingContext,
+    MUTE_TOPICS
+  );
+
+  let microphoneMuted2 = waitForMicrophoneMuteState(browser2, true);
+  let cameraMuted2 = waitForCameraMuteState(browser2, true);
+  info("Sharing the microphone and camera from a new process.");
+  await shareDevices(
+    browser2,
+    true /* camera */,
+    true /* microphone */,
+    false /* screen */
+  );
+  await Promise.all([microphoneMuted2, cameraMuted2]);
+
+  info("Unmuting microphone...");
+  let microphoneUnmuted = Promise.all([
+    waitForMicrophoneMuteState(browser1, false),
+    waitForMicrophoneMuteState(browser2, false),
+  ]);
+  microphoneMute.click();
+  await microphoneUnmuted;
+  info("Microphone successfully unmuted.");
+
+  info("Unmuting camera...");
+  let cameraUnmuted = Promise.all([
+    waitForCameraMuteState(browser1, false),
+    waitForCameraMuteState(browser2, false),
+  ]);
+  cameraMute.click();
+  await cameraUnmuted;
+  info("Camera successfully unmuted.");
+
+  await BrowserTestUtils.stopObservingTopics(
+    browser1.browsingContext,
+    MUTE_TOPICS
+  );
+
+  await BrowserTestUtils.stopObservingTopics(
+    browser2.browsingContext,
+    MUTE_TOPICS
+  );
+
+  BrowserTestUtils.removeTab(tab2);
+  BrowserTestUtils.removeTab(tab1);
+});