diff --git a/browser_patches/firefox/BUILD_NUMBER b/browser_patches/firefox/BUILD_NUMBER
index 65a581ef24..550e78d53a 100644
--- a/browser_patches/firefox/BUILD_NUMBER
+++ b/browser_patches/firefox/BUILD_NUMBER
@@ -1,2 +1,2 @@
-1160
-Changed: lushnikov@chromium.org Thu Aug 13 23:10:17 PDT 2020
+1161
+Changed: yurys@chromium.org Wed Aug 19 11:51:52 PDT 2020
diff --git a/browser_patches/firefox/juggler/TargetRegistry.js b/browser_patches/firefox/juggler/TargetRegistry.js
index 105ec0702f..00980bc775 100644
--- a/browser_patches/firefox/juggler/TargetRegistry.js
+++ b/browser_patches/firefox/juggler/TargetRegistry.js
@@ -198,7 +198,7 @@ class TargetRegistry {
         setViewportSizeForBrowser(browserContext.defaultViewportSize, tab.linkedBrowser, window);
     };
 
-    const onTabCloseListener = event => {
+    const onTabCloseListener = async event => {
       const tab = event.target;
       const linkedBrowser = tab.linkedBrowser;
       const target = this._browserToTarget.get(linkedBrowser);
@@ -497,6 +497,7 @@ class BrowserContext {
     this.ignoreHTTPSErrors = undefined;
     this.downloadOptions = undefined;
     this.defaultViewportSize = undefined;
+    this.screencastOptions = undefined;
     this.scriptsToEvaluateOnNewDocument = [];
     this.bindings = [];
     this.settings = {};
@@ -684,6 +685,10 @@ class BrowserContext {
     }
     return result;
   }
+
+  setScreencastOptions(options) {
+    this.screencastOptions = options;
+  }
 }
 
 function dirPath(path) {
diff --git a/browser_patches/firefox/juggler/protocol/BrowserHandler.js b/browser_patches/firefox/juggler/protocol/BrowserHandler.js
index 50e7a9ba38..9b960add61 100644
--- a/browser_patches/firefox/juggler/protocol/BrowserHandler.js
+++ b/browser_patches/firefox/juggler/protocol/BrowserHandler.js
@@ -64,11 +64,11 @@ class BrowserHandler {
     this._createdBrowserContextIds.delete(browserContextId);
   }
 
-  dispose() {
+  async dispose() {
     helper.removeListeners(this._eventListeners);
     for (const [target, session] of this._attachedSessions) {
       target.disconnectSession(session);
-      this._dispatcher.destroySession(session);
+      await this._dispatcher.destroySession(session);
     }
     this._attachedSessions.clear();
     for (const browserContextId of this._createdBrowserContextIds) {
@@ -99,12 +99,12 @@ class BrowserHandler {
     sessions.push(session);
   }
 
-  _onTargetDestroyed(target) {
+  async _onTargetDestroyed(target) {
     const session = this._attachedSessions.get(target);
     if (!session)
       return;
     this._attachedSessions.delete(target);
-    this._dispatcher.destroySession(session);
+    await this._dispatcher.destroySession(session);
     this._session.emitEvent('Browser.detachedFromTarget', {
       sessionId: session.sessionId(),
       targetId: target.id(),
@@ -184,6 +184,10 @@ class BrowserHandler {
     await this._targetRegistry.browserContextForId(browserContextId).applySetting('colorScheme', nullToUndefined(colorScheme));
   }
 
+  async setScreencastOptions({browserContextId, dir, width, height, scale}) {
+    await this._targetRegistry.browserContextForId(browserContextId).setScreencastOptions({dir, width, height, scale});
+  }
+
   async setUserAgentOverride({browserContextId, userAgent}) {
     await this._targetRegistry.browserContextForId(browserContextId).applySetting('userAgent', nullToUndefined(userAgent));
   }
diff --git a/browser_patches/firefox/juggler/protocol/Dispatcher.js b/browser_patches/firefox/juggler/protocol/Dispatcher.js
index 2f0413f981..c90903fcb4 100644
--- a/browser_patches/firefox/juggler/protocol/Dispatcher.js
+++ b/browser_patches/firefox/juggler/protocol/Dispatcher.js
@@ -29,9 +29,9 @@ class Dispatcher {
     return session;
   }
 
-  destroySession(session) {
-    session.dispose();
+  async destroySession(session) {
     this._sessions.delete(session.sessionId());
+    await session.dispose();
   }
 
   _dispose() {
@@ -108,13 +108,15 @@ class ProtocolSession {
     this._handlers.set(domainName, handler);
   }
 
-  dispose() {
+  async dispose() {
+    const promises = [];
     for (const [domainName, handler] of this._handlers) {
       if (typeof handler.dispose !== 'function')
         throw new Error(`Handler for "${domainName}" domain does not define |dispose| method!`);
-      handler.dispose();
+      promises.push(handler.dispose());
     }
     this._handlers.clear();
+    await Promise.all(promises);
     this._dispatcher = null;
   }
 
diff --git a/browser_patches/firefox/juggler/protocol/PageHandler.js b/browser_patches/firefox/juggler/protocol/PageHandler.js
index 4deb05fba6..523f12d41e 100644
--- a/browser_patches/firefox/juggler/protocol/PageHandler.js
+++ b/browser_patches/firefox/juggler/protocol/PageHandler.js
@@ -6,6 +6,7 @@
 
 const {Helper} = ChromeUtils.import('chrome://juggler/content/Helper.js');
 const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const {OS} = ChromeUtils.import("resource://gre/modules/osfile.jsm");
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
@@ -132,13 +133,19 @@ class PageHandler {
         this._session.emitEvent('Page.crashed', {});
       }),
     ]);
+
+    const options = this._pageTarget.browserContext().screencastOptions;
+    if (options) {
+      const file = OS.Path.join(options.dir, helper.generateId() + '.webm');
+      await this.startVideoRecording(Object.assign({file}, options));
+    }
   }
 
-  dispose() {
+  async dispose() {
     this._contentPage.dispose();
     helper.removeListeners(this._eventListeners);
     if (this._videoSessionId !== -1)
-      this.stopVideoRecording().catch(e => dump(`stopVideoRecording failed:\n${e}\n`));
+      await this.stopVideoRecording().catch(e => dump(`stopVideoRecording failed:\n${e}\n`));
   }
 
   async setViewportSize({viewportSize}) {
@@ -304,6 +311,7 @@ class PageHandler {
     const rect = this._pageTarget.linkedBrowser().getBoundingClientRect();
     const devicePixelRatio = this._pageTarget._window.devicePixelRatio;
     this._videoSessionId = screencast.startVideoRecording(docShell, file, width, height, scale || 0, devicePixelRatio * rect.top);
+    this._session.emitEvent('Page.screencastStarted', {uid: '' + this._videoSessionId, file});
   }
 
   async stopVideoRecording() {
@@ -312,6 +320,7 @@ class PageHandler {
     const videoSessionId = this._videoSessionId;
     this._videoSessionId = -1;
     const screencast = Cc['@mozilla.org/juggler/screencast;1'].getService(Ci.nsIScreencastService);
+    const session = this._session;
     const result = new Promise(resolve =>
       Services.obs.addObserver(function onStopped(subject, topic, data) {
         if (videoSessionId != data)
@@ -319,6 +328,8 @@ class PageHandler {
 
         Services.obs.removeObserver(onStopped, 'juggler-screencast-stopped');
         resolve();
+
+        session.emitEvent('Page.screencastStopped', {uid: '' + videoSessionId});
       }, 'juggler-screencast-stopped')
     );
     screencast.stopVideoRecording(videoSessionId);
diff --git a/browser_patches/firefox/juggler/protocol/Protocol.js b/browser_patches/firefox/juggler/protocol/Protocol.js
index 5a6822694e..f47b73e449 100644
--- a/browser_patches/firefox/juggler/protocol/Protocol.js
+++ b/browser_patches/firefox/juggler/protocol/Protocol.js
@@ -407,6 +407,15 @@ const Browser = {
         colorScheme: t.Nullable(t.Enum(['dark', 'light', 'no-preference'])),
       },
     },
+    'setScreencastOptions': {
+      params: {
+        browserContextId: t.Optional(t.String),
+        dir: t.String,
+        width: t.Number,
+        height: t.Number,
+        scale: t.Optional(t.Number),
+      },
+    },
   },
 };
 
@@ -640,6 +649,13 @@ const Page = {
       workerId: t.String,
       message: t.String,
     },
+    'screencastStarted': {
+      uid: t.String,
+      file: t.String,
+    },
+    'screencastStopped': {
+      uid: t.String,
+    },
   },
 
   methods: {