Reland of ll closure compiler and update sources (patchset #1 id:1 of https://codereview.chromium.org/1661853004/ )

Reason for revert:
My revert is breaking the compile

note: Running closure compiler on suggestion_controller.js
note: Running closure compiler on autofill_controller.js
java -jar ../third_party/closure_compiler/compiler/compiler.jar --compilation_level SIMPLE_OPTIMIZATIONS "--jscomp_error=accessControls" "--jscomp_error=ambiguousFunctionDecl" "--jscomp_error=constantProperty" "--jscomp_error=deprecated" "--jscomp_error=externsValidation" "--jscomp_error=globalThis" "--jscomp_error=invalidCasts" "--jscomp_error=nonStandardJsDocs" "--jscomp_error=suspiciousCode" "--jscomp_error=undefinedNames" "--jscomp_error=unknownDefines" "--jscomp_error=uselessCode" "--jscomp_error=visibility" --js "autofill/ios/browser/resources/suggestion_controller.js" --js_output_file "/b/build/slave/iOS_Device/build/src/xcodebuild/DerivedSources/Release/suggestion_controller.js"
java -jar ../third_party/closure_compiler/compiler/compiler.jar --compilation_level SIMPLE_OPTIMIZATIONS "--jscomp_error=accessControls" "--jscomp_error=ambiguousFunctionDecl" "--jscomp_error=constantProperty" "--jscomp_error=deprecated" "--jscomp_error=externsValidation" "--jscomp_error=globalThis" "--jscomp_error=invalidCasts" "--jscomp_error=nonStandardJsDocs" "--jscomp_error=suspiciousCode" "--jscomp_error=undefinedNames" "--jscomp_error=unknownDefines" "--jscomp_error=uselessCode" "--jscomp_error=visibility" --js "autofill/ios/browser/resources/autofill_controller.js" --js_output_file "/b/build/slave/iOS_Device/build/src/xcodebuild/DerivedSources/Release/autofill_controller.js"
Error: Invalid or corrupt jarfile ../third_party/closure_compiler/compiler/compiler.jarError: Invalid or corrupt jarfile ../third_party/closure_compiler/compiler/compiler.jar

make: *** [/b/build/slave/iOS_Device/build/src/xcodebuild/DerivedSources/Release/autofill_controller.js] Error 1
make: *** Waiting for unfinished jobs....
make: *** [/b/build/slave/iOS_Device/build/src/xcodebuild/DerivedSources/Release/suggestion_controller.js] Error 1
Command /bin/sh failed with exit code 2

Original issue's description:
> Revert of Roll closure compiler and update sources (patchset #6 id:140001 of https://codereview.chromium.org/1473723002/ )
>
> Reason for revert:
> Breaks the FirstRunUIBrowserTest.FirstRunFlow
>
> See the log while it's hot:
> https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/11491/steps/browser_tests/logs/FirstRunUIBrowserTest.FirstRunFlow
>
> Relevant bits:
> ...
> [28690:28690:0202/170602:ERROR:CONSOLE(31)] "Uncaught Error: Assertion failed: [object SVGSVGElement] is not a[n] HTMLElement", source: chrome://resources/js/util.js (31)
> BrowserTestBase signal handler received SIGTERM. Backtrace:
> #0 0x7f32d1d6496e base::debug::StackTrace::StackTrace()
> #1 0x0000024791da content::(anonymous namespace)::DumpStackTraceSignalHandler()
> #2 0x7f32bf3a7150 <unknown>
> #3 0x7f32bf4589d3 __poll
> #4 0x7f32c0142ff6 <unknown>
> ....
>
> Original issue's description:
> > Roll closure compiler and update sources
> >
> > Change log:
> > https://github.com/google/closure-compiler/compare/53f3d8a41579c002ec656bb645ce5d54470f6e0b...972497be96e537b8eee93fbeb367ede9c878df7a
> > chrome_extensions.js: 56292b9c2ae3991e75c0c8d5e86ef91a94058d2e -> a40c181d7d0f0e35ced922d0d8c935821b8ab214
> >
> > Update $() to return HTMLElement.
> > Add a base.getHtmlElement to remoting.
> >
> > BUG=
> > R=dbeam@chromium.org, hirono@chromium.org, jamiewalch@chromium.org, stevenjb@chromium.org
> >
> > Committed: https://chromium.googlesource.com/chromium/src/+/3d7d66a9c117d92000e87d75509bdc12d79aa455
>
> TBR=dbeam@chromium.org,tbreisacher@chromium.org,jamiewalch@chromium.org,mtomasz@chromium.org,hirono@chromium.org,stevenjb@chromium.org,rdevlin.cronin@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/9f7d03b5af98c508629ed52a18fa222e6996db5f
> Cr-Commit-Position: refs/heads/master@{#373233}

TBR=dbeam@chromium.org,tbreisacher@chromium.org,jamiewalch@chromium.org,mtomasz@chromium.org,hirono@chromium.org,stevenjb@chromium.org,rdevlin.cronin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1660373003

Cr-Commit-Position: refs/heads/master@{#373236}

30 files changed, 106 insertions, 66 deletions

diff --git a/chrome/browser/resources/bookmark_manager/js/main.js b/chrome/browser/resources/bookmark_manager/js/main.js
index 7dc284f..48e74f2 100644
--- a/chrome/browser/resources/bookmark_manager/js/main.js
+++ b/chrome/browser/resources/bookmark_manager/js/main.js
@@ -295,7 +295,7 @@ function setSearch(searchText) {
  * This returns the user visible path to the folder where the bookmark is
  * located.
  * @param {number} parentId The ID of the parent folder.
- * @return {string} The path to the the bookmark,
+ * @return {string|undefined} The path to the the bookmark,
  */
 function getFolder(parentId) {
   var parentNode = bmm.tree.getBookmarkNodeById(parentId);
diff --git a/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.js b/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.js
index 3e3babf..72f6398 100644
--- a/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.js
+++ b/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.js
@@ -780,8 +780,8 @@ Polymer({
    * castModeList.
    *
    * @param {number} castModeType Type of cast mode to look for.
-   * @return {?media_router.CastMode} CastMode object with the given type in
-   *     castModeList, or undefined if not found.
+   * @return {media_router.CastMode|undefined} CastMode object with the given
+   *     type in castModeList, or undefined if not found.
    */
   findCastModeByType_: function(castModeType) {
     return this.castModeList.find(function(element, index, array) {
diff --git a/chrome/browser/resources/options/chromeos/display_options.js b/chrome/browser/resources/options/chromeos/display_options.js
index ce93d1f..600451d 100644
--- a/chrome/browser/resources/options/chromeos/display_options.js
+++ b/chrome/browser/resources/options/chromeos/display_options.js
@@ -346,7 +346,7 @@ cr.define('options', function() {
 
     /**
      * @param {string} id
-     * @return {options.DisplayInfo}
+     * @return {!options.DisplayInfo|undefined}
      */
     getDisplayInfoFromId_(id) {
       return this.displays_.find(function(display) {
diff --git a/chrome/browser/resources/settings/bluetooth_page/bluetooth_page.js b/chrome/browser/resources/settings/bluetooth_page/bluetooth_page.js
index c8babf4..47f4efd 100644
--- a/chrome/browser/resources/settings/bluetooth_page/bluetooth_page.js
+++ b/chrome/browser/resources/settings/bluetooth_page/bluetooth_page.js
@@ -416,7 +416,7 @@ Polymer({
    * @private
    */
   haveDevices_: function(deviceListChanges) {
-    return this.deviceList.findIndex(function(d) { return d.paired; }) != -1;
+    return this.deviceList.findIndex(function(d) { return !!d.paired; }) != -1;
   },
 
   /**
diff --git a/remoting/webapp/app_remoting/js/app_connected_view.js b/remoting/webapp/app_remoting/js/app_connected_view.js
index f3d05be..6918a1e 100644
--- a/remoting/webapp/app_remoting/js/app_connected_view.js
+++ b/remoting/webapp/app_remoting/js/app_connected_view.js
@@ -49,7 +49,7 @@ remoting.AppConnectedView = function(containerElement, windowShape,
   // Initialize the context menus.
   if (!remoting.platformIsChromeOS()) {
     menuAdapter = new remoting.ContextMenuDom(
-        document.getElementById('context-menu'), windowShape);
+        base.getHtmlElement('context-menu'), windowShape);
   }
 
   this.contextMenu_ = new remoting.ApplicationContextMenu(
diff --git a/remoting/webapp/app_remoting/js/app_remoting_activity.js b/remoting/webapp/app_remoting/js/app_remoting_activity.js
index b1930bad3..aff04df 100644
--- a/remoting/webapp/app_remoting/js/app_remoting_activity.js
+++ b/remoting/webapp/app_remoting/js/app_remoting_activity.js
@@ -180,11 +180,11 @@ remoting.AppRemotingActivity.prototype.onAppHostResponse_ =
  */
 remoting.AppRemotingActivity.prototype.onConnected = function(connectionInfo) {
   var connectedView = new remoting.AppConnectedView(
-      document.getElementById('client-container'),
+      base.getHtmlElement('client-container'),
       this.windowShape_, connectionInfo, this.windowMessageDispatcher_);
 
   var idleDetector = new remoting.IdleDetector(
-      document.getElementById('idle-dialog'),
+      base.getHtmlElement('idle-dialog'),
       this.windowShape_,
       this.app_.getApplicationName(),
       this.stop.bind(this));
diff --git a/remoting/webapp/base/js/application.js b/remoting/webapp/base/js/application.js
index 8fac258..723e0a1 100644
--- a/remoting/webapp/base/js/application.js
+++ b/remoting/webapp/base/js/application.js
@@ -111,18 +111,25 @@ remoting.Application.prototype.getExtensionInfo = function() {
  * These functions must be overridden in the subclass.
  */
 
-/** @return {string} */
+/**
+ * @return {string}
+ * @suppress {missingReturn}
+ */
 remoting.Application.prototype.getApplicationId = function() {
   console.assert(false, 'Subclass must override');
 };
 
-/** @return {string} */
+/**
+ * @return {string}
+ * @suppress {missingReturn}
+ */
 remoting.Application.prototype.getApplicationName = function() {
   console.assert(false, 'Subclass must override getApplicationName().');
 };
 
 /**
  * @return {remoting.Activity}  The Current activity.
+ * @suppress {missingReturn}
  */
 remoting.Application.prototype.getActivity = function() {
   console.assert(false, 'Subclass must override getActivity().');
diff --git a/remoting/webapp/base/js/base.js b/remoting/webapp/base/js/base.js
index 6f11278..f51181e 100644
--- a/remoting/webapp/base/js/base.js
+++ b/remoting/webapp/base/js/base.js
@@ -861,3 +861,15 @@ base.isNaclEnabled = function() {
   }
   return false;
 };
+
+/**
+ * Alias for document.getElementById that returns an HTMLElement
+ * @param {string} id The ID of the element to find.
+ * @return {?HTMLElement} The found element or null if not found.
+ */
+base.getHtmlElement = function(id) {
+  var el = document.getElementById(id);
+  if (el)
+    console.assert(el instanceof HTMLElement);
+  return /** @type {HTMLElement} */(el);
+};
diff --git a/remoting/webapp/base/js/message_window.js b/remoting/webapp/base/js/message_window.js
index f0eb428..54654ce 100644
--- a/remoting/webapp/base/js/message_window.js
+++ b/remoting/webapp/base/js/message_window.js
@@ -48,9 +48,9 @@ MessageWindowImpl.prototype.sendReply_ = function(
  * Initializes the button with the label and the click handler.
  * Hides the button if the label is null or undefined.
  *
- * @param{HTMLElement} button
- * @param{?string} label
- * @param{Function} clickHandler
+ * @param {HTMLElement} button
+ * @param {?string} label
+ * @param {Function} clickHandler
  * @private
  */
 MessageWindowImpl.prototype.initButton_ =
@@ -92,12 +92,12 @@ MessageWindowImpl.prototype.onMessage_ = function(event) {
       }
 
       // Set the dialog text.
-      var button = document.getElementById('button-primary');
-      var cancelButton = document.getElementById('button-secondary');
-      var messageDiv = document.getElementById('message');
-      var infoboxDiv = document.getElementById('infobox');
+      var button = base.getHtmlElement('button-primary');
+      var cancelButton = base.getHtmlElement('button-secondary');
+      var messageDiv = base.getHtmlElement('message');
+      var infoboxDiv = base.getHtmlElement('infobox');
 
-      document.getElementById('title').innerText = title;
+      base.getHtmlElement('title').innerText = title;
       document.querySelector('title').innerText = title;
       messageDiv.innerHTML = message;
 
@@ -142,7 +142,7 @@ MessageWindowImpl.prototype.onMessage_ = function(event) {
         break;
       }
 
-      var messageDiv = document.getElementById('message');
+      var messageDiv = base.getHtmlElement('message');
       messageDiv.innerText = message;
 
       base.resizeWindowToContent(true);
diff --git a/remoting/webapp/base/js/modal_dialogs.js b/remoting/webapp/base/js/modal_dialogs.js
index e6b750d..4279401 100644
--- a/remoting/webapp/base/js/modal_dialogs.js
+++ b/remoting/webapp/base/js/modal_dialogs.js
@@ -149,7 +149,6 @@ remoting.MessageDialog.prototype.dispose = function() {
 
 /**
  * @param {remoting.MessageDialog.Result} result
- * @return {Function}
  * @private
  */
 remoting.MessageDialog.prototype.onClicked_ = function(result) {
@@ -270,7 +269,7 @@ remoting.ConnectingDialog = function(cancelCallback) {
   /** @private */
   this.dialog_ = new remoting.MessageDialog(
       remoting.AppMode.CLIENT_CONNECTING,
-      document.getElementById('cancel-connect-button'));
+      base.getHtmlElement('cancel-connect-button'));
   /** @private */
   this.onCancel_ = cancelCallback;
 };
diff --git a/remoting/webapp/browser_test/timeout_waiter.js b/remoting/webapp/browser_test/timeout_waiter.js
index cb1a3a4..0c5a35c 100644
--- a/remoting/webapp/browser_test/timeout_waiter.js
+++ b/remoting/webapp/browser_test/timeout_waiter.js
@@ -70,7 +70,7 @@ browserTest.isVisible = function(id) {
   var pred = new browserTest.Predicate();
   pred.evaluate = function() {
     /** @type {HTMLElement} */
-    var element = document.getElementById(id);
+    var element = base.getHtmlElement(id);
     browserTest.expect(Boolean(element), 'No such element: ' + id);
     return element.getBoundingClientRect().width !== 0;
   };
diff --git a/remoting/webapp/crd/js/crd_auth_dialog.js b/remoting/webapp/crd/js/crd_auth_dialog.js
index 8d45bde..f57c5b3 100644
--- a/remoting/webapp/crd/js/crd_auth_dialog.js
+++ b/remoting/webapp/crd/js/crd_auth_dialog.js
@@ -67,7 +67,7 @@ remoting.AuthDialog.prototype.isVisible = function() {
  */
 remoting.AuthDialog.getInstance = function() {
   if (!instance_) {
-    var rootElement = document.getElementById('auth-dialog');
+    var rootElement = base.getHtmlElement('auth-dialog');
     instance_ = new remoting.AuthDialog(rootElement);
   }
   return instance_;
diff --git a/remoting/webapp/crd/js/crd_main.js b/remoting/webapp/crd/js/crd_main.js
index d83a1bf..0ce20ae 100644
--- a/remoting/webapp/crd/js/crd_main.js
+++ b/remoting/webapp/crd/js/crd_main.js
@@ -16,11 +16,11 @@ var remoting = remoting || {};
 remoting.initHostlist_ = function(handleConnect) {
   remoting.hostController = new remoting.HostController();
   remoting.hostList = new remoting.HostList(
-      document.getElementById('host-list'),
-      document.getElementById('host-list-empty'),
-      document.getElementById('host-list-error-message'),
-      document.getElementById('host-list-refresh-failed-button'),
-      document.getElementById('host-list-loading-indicator'),
+      base.getHtmlElement('host-list'),
+      base.getHtmlElement('host-list-empty'),
+      base.getHtmlElement('host-list-error-message'),
+      base.getHtmlElement('host-list-refresh-failed-button'),
+      base.getHtmlElement('host-list-loading-indicator'),
       remoting.showErrorMessage,
       handleConnect);
 
@@ -68,13 +68,13 @@ function isHostModeSupported_() {
  */
 remoting.initHomeScreenUi = function() {
   remoting.setMode(remoting.AppMode.HOME);
-  var dialog = document.getElementById('paired-clients-list');
-  var message = document.getElementById('paired-client-manager-message');
-  var deleteAll = document.getElementById('delete-all-paired-clients');
-  var close = document.getElementById('close-paired-client-manager-dialog');
-  var working = document.getElementById('paired-client-manager-dialog-working');
-  var error = document.getElementById('paired-client-manager-dialog-error');
-  var noPairedClients = document.getElementById('no-paired-clients');
+  var dialog = base.getHtmlElement('paired-clients-list');
+  var message = base.getHtmlElement('paired-client-manager-message');
+  var deleteAll = base.getHtmlElement('delete-all-paired-clients');
+  var close = base.getHtmlElement('close-paired-client-manager-dialog');
+  var working = base.getHtmlElement('paired-client-manager-dialog-working');
+  var error = base.getHtmlElement('paired-client-manager-dialog-error');
+  var noPairedClients = base.getHtmlElement('no-paired-clients');
   remoting.pairedClientManager =
       new remoting.PairedClientManager(remoting.hostController, dialog, message,
                                        deleteAll, close, noPairedClients,
diff --git a/remoting/webapp/crd/js/desktop_connected_view.js b/remoting/webapp/crd/js/desktop_connected_view.js
index 22cbf4b..d06a5a2 100644
--- a/remoting/webapp/crd/js/desktop_connected_view.js
+++ b/remoting/webapp/crd/js/desktop_connected_view.js
@@ -178,7 +178,7 @@ remoting.DesktopConnectedView.prototype.initUI_ = function() {
       this.plugin_, this.container_,
       this.container_.querySelector('.mouse-cursor-overlay'));
 
-  var scrollerElement = document.getElementById('scroller');
+  var scrollerElement = base.getHtmlElement('scroller');
   this.viewport_ = new remoting.DesktopViewport(
       scrollerElement || document.body,
       this.plugin_.hostDesktop(),
diff --git a/remoting/webapp/crd/js/desktop_remoting.js b/remoting/webapp/crd/js/desktop_remoting.js
index 003cef3..3a0157094 100644
--- a/remoting/webapp/crd/js/desktop_remoting.js
+++ b/remoting/webapp/crd/js/desktop_remoting.js
@@ -96,7 +96,7 @@ remoting.DesktopRemoting.prototype.initApplication_ = function() {
 
   if (base.isAppsV2()) {
     remoting.windowFrame = new remoting.WindowFrame(
-        document.getElementById('title-bar'), this.disconnect_.bind(this));
+        base.getHtmlElement('title-bar'), this.disconnect_.bind(this));
     remoting.optionsMenu = remoting.windowFrame.createOptionsMenu();
 
     var START_FULLSCREEN = 'start-fullscreen';
@@ -120,7 +120,7 @@ remoting.DesktopRemoting.prototype.initApplication_ = function() {
   } else {
     remoting.fullscreen = new remoting.FullscreenAppsV1();
     remoting.toolbar = new remoting.Toolbar(
-        document.getElementById('session-toolbar'),
+        base.getHtmlElement('session-toolbar'),
         this.disconnect_.bind(this));
     remoting.optionsMenu = remoting.toolbar.createOptionsMenu();
 
@@ -133,8 +133,7 @@ remoting.DesktopRemoting.prototype.initApplication_ = function() {
   document.getElementById('access-mode-button').addEventListener(
       'click', this.connectIt2Me_.bind(this), false);
 
-  remoting.manageHelpAndFeedback(
-      document.getElementById('title-bar'));
+  remoting.manageHelpAndFeedback(base.getHtmlElement('title-bar'));
 
   remoting.showOrHideIT2MeUi();
   remoting.showOrHideMe2MeUi();
diff --git a/remoting/webapp/crd/js/desktop_remoting_activity.js b/remoting/webapp/crd/js/desktop_remoting_activity.js
index 06ebd78..cf516a8 100644
--- a/remoting/webapp/crd/js/desktop_remoting_activity.js
+++ b/remoting/webapp/crd/js/desktop_remoting_activity.js
@@ -95,7 +95,7 @@ remoting.DesktopRemotingActivity.prototype.onConnected =
   }
 
   this.connectedView_ = remoting.DesktopConnectedView.create(
-      document.getElementById('client-container'), connectionInfo);
+      base.getHtmlElement('client-container'), connectionInfo);
 
   // Apply the default or previously-specified keyboard remapping.
   var remapping = connectionInfo.host().options.getRemapKeys();
diff --git a/remoting/webapp/crd/js/host_table_entry.js b/remoting/webapp/crd/js/host_table_entry.js
index 89845a0..d5bae00 100644
--- a/remoting/webapp/crd/js/host_table_entry.js
+++ b/remoting/webapp/crd/js/host_table_entry.js
@@ -134,7 +134,7 @@ remoting.HostTableEntry.prototype.createDom_ = function() {
   }
 };
 
-/** @return {base.Disposable} @private */
+/** @private */
 remoting.HostTableEntry.prototype.registerButton_ = function(
     /** HTMLElement */ button, /** Function */ callback) {
   var onKeyDown = function(/** Event */ e) {
diff --git a/remoting/webapp/crd/js/it2me_activity.js b/remoting/webapp/crd/js/it2me_activity.js
index 1e69c63..3d4e102 100644
--- a/remoting/webapp/crd/js/it2me_activity.js
+++ b/remoting/webapp/crd/js/it2me_activity.js
@@ -24,7 +24,7 @@ remoting.It2MeActivity = function() {
   /** @private */
   this.passCode_ = '';
 
-  var form = document.getElementById('access-code-form');
+  var form = base.getHtmlElement('access-code-form');
   /** @private */
   this.accessCodeDialog_ = remoting.modalDialogFactory.createInputDialog(
     remoting.AppMode.CLIENT_UNCONNECTED,
@@ -151,7 +151,7 @@ remoting.It2MeActivity.prototype.getDesktopActivityForTesting = function() {
 remoting.It2MeActivity.prototype.showFinishDialog_ = function(mode) {
   var finishDialog = new remoting.MessageDialog(
       mode,
-      document.getElementById('client-finished-it2me-button'));
+      base.getHtmlElement('client-finished-it2me-button'));
   finishDialog.show().then(function() {
     remoting.setMode(remoting.AppMode.HOME);
   });
diff --git a/remoting/webapp/crd/js/me2me_activity.js b/remoting/webapp/crd/js/me2me_activity.js
index d2bcbdc..aa43d8a 100644
--- a/remoting/webapp/crd/js/me2me_activity.js
+++ b/remoting/webapp/crd/js/me2me_activity.js
@@ -23,10 +23,10 @@ remoting.Me2MeActivity = function(host, hostList) {
   this.hostList_ = hostList;
   /** @private */
   this.pinDialog_ =
-      new remoting.PinDialog(document.getElementById('pin-dialog'), host);
+      new remoting.PinDialog(base.getHtmlElement('pin-dialog'), host);
   /** @private */
   this.hostUpdateDialog_ = new remoting.HostNeedsUpdateDialog(
-      document.getElementById('host-needs-update-dialog'), this.host_);
+      base.getHtmlElement('host-needs-update-dialog'), this.host_);
 
   /** @private */
   this.retryOnHostOffline_ = true;
@@ -282,8 +282,8 @@ remoting.Me2MeActivity.prototype.showErrorMessage_ = function(error) {
 remoting.Me2MeActivity.prototype.showFinishDialog_ = function(mode) {
   var dialog = remoting.modalDialogFactory.createMessageDialog(
       mode,
-      document.getElementById('client-finished-me2me-button'),
-      document.getElementById('client-reconnect-button'));
+      base.getHtmlElement('client-finished-me2me-button'),
+      base.getHtmlElement('client-reconnect-button'));
 
   /** @typedef {remoting.MessageDialog.Result} */
   var Result = remoting.MessageDialog.Result;
diff --git a/remoting/webapp/crd/js/third_party_host_permissions.js b/remoting/webapp/crd/js/third_party_host_permissions.js
index 1fd3edf..e8bc2d4 100644
--- a/remoting/webapp/crd/js/third_party_host_permissions.js
+++ b/remoting/webapp/crd/js/third_party_host_permissions.js
@@ -66,9 +66,9 @@ remoting.ThirdPartyHostPermissions.prototype.getPermission = function(
 remoting.ThirdPartyHostPermissions.prototype.showPermissionConfirmation_ =
     function(onOk, onError) {
   /** @type {HTMLElement} */
-  var button = document.getElementById('third-party-auth-button');
+  var button = base.getHtmlElement('third-party-auth-button');
   /** @type {HTMLElement} */
-  var url = document.getElementById('third-party-auth-url');
+  var url = base.getHtmlElement('third-party-auth-url');
   url.innerText = this.url_;
 
   /** @type {remoting.ThirdPartyHostPermissions} */
diff --git a/remoting/webapp/crd/js/xhr_proxy.js b/remoting/webapp/crd/js/xhr_proxy.js
index 42ff883..dd24d7d 100644
--- a/remoting/webapp/crd/js/xhr_proxy.js
+++ b/remoting/webapp/crd/js/xhr_proxy.js
@@ -65,10 +65,12 @@ remoting.XMLHttpRequestProxy.prototype.abort = function() {
   }
 };
 
+/** @suppress {missingReturn} */
 remoting.XMLHttpRequestProxy.prototype.getResponseHeader = function(header) {
   console.error('Sandbox: unproxied getResponseHeader(' + header + ') called.');
 };
 
+/** @suppress {missingReturn} */
 remoting.XMLHttpRequestProxy.prototype.getAllResponseHeaders = function() {
   console.error('Sandbox: unproxied getAllResponseHeaders called.');
 };
diff --git a/remoting/webapp/js_proto/dom_proto.js b/remoting/webapp/js_proto/dom_proto.js
index c47c990..58b48c0 100644
--- a/remoting/webapp/js_proto/dom_proto.js
+++ b/remoting/webapp/js_proto/dom_proto.js
@@ -54,9 +54,6 @@ Element.prototype.offsetBottom;
 /** @type {string} */
 Element.prototype.textContent;
 
-/** @type {DOMTokenList} */
-Element.prototype.classList;
-
 /** @type {boolean} */
 Element.prototype.checked;
 
diff --git a/third_party/closure_compiler/README.chromium b/third_party/closure_compiler/README.chromium
index 86a8278..1a04bbd 100644
--- a/third_party/closure_compiler/README.chromium
+++ b/third_party/closure_compiler/README.chromium
@@ -3,7 +3,7 @@ Short Name: closure-compiler
 URL: http://github.com/google/closure-compiler
 Version: v20150729-236-gad656a1
 Date: 2015/08/26 08:46
-Revision: 53f3d8a41579c002ec656bb645ce5d54470f6e0b
+Revision: 972497be96e537b8eee93fbeb367ede9c878df7a
 License: Apache 2.0
 License File: LICENSE
 Security Critical: no
diff --git a/third_party/closure_compiler/externs/chrome_extensions.js b/third_party/closure_compiler/externs/chrome_extensions.js
index 787e808..656a6a7 100644
--- a/third_party/closure_compiler/externs/chrome_extensions.js
+++ b/third_party/closure_compiler/externs/chrome_extensions.js
@@ -6,7 +6,7 @@
 // S:::::S                    T:::::T        O:::::O     O:::::O  P::::P     P:::::P
 //  S::::SSSS                                                     P::::PPPPPP:::::P
 //   SS::::::SSSSS       This file is generated. To update it,    P:::::::::::::PP
-//     SSS::::::::SS          run roll_compiler_version.          P::::PPPPPPPPP
+//     SSS::::::::SS          run roll_closure_compiler.          P::::PPPPPPPPP
 //        SSSSSS::::S                                             P::::P
 //             S:::::S        T:::::T        O:::::O     O:::::O  P::::P
 //             S:::::S        T:::::T        O::::::O   O::::::O  P::::P
@@ -403,14 +403,14 @@ chrome.app.window.AppWindow.prototype.hide = function() {};
 
 
 /**
- * @return {!chrome.app.window.Bounds} The current window bounds.
+ * @return {!chrome.app.window.ContentBounds} The current window bounds.
  * @see http://developer.chrome.com/apps/app.window.html#type-AppWindow
  */
 chrome.app.window.AppWindow.prototype.getBounds = function() {};
 
 
 /**
- * @param {!chrome.app.window.Bounds} bounds The new window bounds.
+ * @param {!chrome.app.window.ContentBounds} bounds The new window bounds.
  * @see http://developer.chrome.com/apps/app.window.html#type-AppWindow
  */
 chrome.app.window.AppWindow.prototype.setBounds = function(bounds) {};
@@ -431,6 +431,24 @@ chrome.app.window.AppWindow.prototype.isAlwaysOnTop = function() {};
 chrome.app.window.AppWindow.prototype.setAlwaysOnTop = function(alwaysOnTop) {};
 
 
+/**
+ * @param {boolean} alwaysVisible Set whether the window is visible on all
+ *     workspaces.
+ * @see http://developer.chrome.com/apps/app.window.html#type-AppWindow
+ */
+chrome.app.window.AppWindow.prototype.setVisibleOnAllWorkspaces =
+    function(alwaysVisible) {};
+
+
+/**
+ * @param {boolean} wantAllKeys Set whether the window should get all keyboard
+ *     events including system keys that are usually not sent.
+ * @see http://developer.chrome.com/apps/app.window.html#type-AppWindow
+ */
+chrome.app.window.AppWindow.prototype.setInterceptAllKeys =
+    function(wantAllKeys) {};
+
+
 /** @type {!ChromeEvent} */
 chrome.app.window.AppWindow.prototype.onBoundsChanged;
 
@@ -459,6 +477,10 @@ chrome.app.window.AppWindow.prototype.onRestored;
 chrome.app.window.AppWindow.prototype.contentWindow;
 
 
+/** @type {string} */
+chrome.app.window.AppWindow.prototype.id;
+
+
 /** @type {!chrome.app.window.Bounds} */
 chrome.app.window.AppWindow.prototype.innerBounds;
 
diff --git a/third_party/closure_compiler/runner/runner.jar b/third_party/closure_compiler/runner/runner.jar
index a7f5f52..2f4542b 100644
--- a/third_party/closure_compiler/runner/runner.jar
+++ b/third_party/closure_compiler/runner/runner.jar
diff --git a/ui/file_manager/file_manager/foreground/js/import_controller.js b/ui/file_manager/file_manager/foreground/js/import_controller.js
index 3e06bfe..73b7f7c 100644
--- a/ui/file_manager/file_manager/foreground/js/import_controller.js
+++ b/ui/file_manager/file_manager/foreground/js/import_controller.js
@@ -516,7 +516,8 @@ importer.ClickSource = {
 importer.RuntimeCommandWidget = function() {
 
   /** @private {HTMLElement} */
-  this.detailsPanel_ = document.getElementById('cloud-import-details');
+  this.detailsPanel_ = /** @type {HTMLElement} */(
+      document.getElementById('cloud-import-details'));
   this.detailsPanel_.addEventListener(
       'transitionend',
       this.onDetailsTransitionEnd_.bind(this),
diff --git a/ui/file_manager/file_manager/foreground/js/ui/banners.js b/ui/file_manager/file_manager/foreground/js/ui/banners.js
index cf6c4d9..8d19ac0 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/banners.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/banners.js
@@ -213,7 +213,7 @@ Banners.prototype.prepareAndShowWelcomeBanner_ = function(type, messageId) {
     more.href = str('GOOGLE_DRIVE_REDEEM_URL');
     var moreInnerButton = util.createChild(
         more, 'imitate-paper-button primary', 'button');
-    moreInnerButton.tabIndex = '-1';
+    moreInnerButton.tabIndex = -1;
     moreInnerButton.textContent = str('DRIVE_WELCOME_CHECK_ELIGIBILITY');
   } else {
     title.textContent = str('DRIVE_WELCOME_TITLE');
@@ -221,7 +221,7 @@ Banners.prototype.prepareAndShowWelcomeBanner_ = function(type, messageId) {
     more.textContent = str('DRIVE_LEARN_MORE');
     more.href = str('GOOGLE_DRIVE_OVERVIEW_URL');
   }
-  more.tabIndex = '21';  // See: go/filesapp-tabindex.
+  more.tabIndex = 21;  // See: go/filesapp-tabindex.
   more.id = 'drive-welcome-link';
   more.target = '_blank';
 
diff --git a/ui/file_manager/file_manager/foreground/js/ui/search_box.js b/ui/file_manager/file_manager/foreground/js/ui/search_box.js
index ff52ec5..e56aa4c 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/search_box.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/search_box.js
@@ -239,7 +239,7 @@ SearchBox.prototype.onKeyDown_ = function(event) {
   if (event.keyIdentifier != 'U+001B' /* Esc */ || this.inputElement.value)
     return;
 
-  this.inputElement.tabIndex = '-1';  // Focus to default element after blur.
+  this.inputElement.tabIndex = -1;  // Focus to default element after blur.
   this.inputElement.blur();
 };
 
@@ -275,8 +275,8 @@ SearchBox.prototype.updateStyles_ = function() {
   var hasFocusOnInput = this.element.classList.contains('has-cursor');
 
   // See go/filesapp-tabindex for tabindexes.
-  this.inputElement.tabIndex = (hasText || hasFocusOnInput) ? '13' : '-1';
-  this.searchButton.tabIndex = (hasText || hasFocusOnInput) ? '-1' : '12';
+  this.inputElement.tabIndex = (hasText || hasFocusOnInput) ? 13 : -1;
+  this.searchButton.tabIndex = (hasText || hasFocusOnInput) ? -1 : 12;
 };
 
 /**
diff --git a/ui/webui/resources/js/compiled_resources.gyp b/ui/webui/resources/js/compiled_resources.gyp
index cbfeab6..6646ce1 100644
--- a/ui/webui/resources/js/compiled_resources.gyp
+++ b/ui/webui/resources/js/compiled_resources.gyp
@@ -32,7 +32,7 @@
     {
       'target_name': 'util',
       'variables': {
-        'depends': ['compiled_resources.gyp:cr'],
+        'depends': ['compiled_resources.gyp:cr', 'assert.js'],
         # TODO(jlklein): Get <(VARIABLES) in transient externs/depends working.
         'externs': ['../../../../third_party/closure_compiler/externs/chrome_send.js'],
       },
diff --git a/ui/webui/resources/js/util.js b/ui/webui/resources/js/util.js
index 3907c52..d67bd72 100644
--- a/ui/webui/resources/js/util.js
+++ b/ui/webui/resources/js/util.js
@@ -5,12 +5,13 @@
 // <include src="assert.js">
 
 /**
- * Alias for document.getElementById.
+ * Alias for document.getElementById. Found elements must be HTMLElements.
  * @param {string} id The ID of the element to find.
  * @return {HTMLElement} The found element or null if not found.
  */
 function $(id) {
-  return document.getElementById(id);
+  var el = document.getElementById(id);
+  return el ? assertInstanceof(el, HTMLElement) : null;
 }
 
 /**