lacros: Fix crash when opening chrome://settings

Lacros uses the chromeOS user-agent string but does not display
ash-specific settings. Historically, webui relied on the user-agent to
determine what platform the browser runs on. The combination of the two
results in webUI settings trying to access ash-only private extension
APIs, causing a crash.

This CL updates the logic to explicitly check platform via gn args via
grit, and plumbs through lacros as a new platform.

This CL has one known problem: grit is not processed for js/cr.js for
some webUI tests. This results on isLacros and isChromeOS returning the
wrong values. This doesn't seem to affect any tests for now, but this is
a problem that should be fixed. This is tracked in
https://crbug.com/1118190.

Bug: 1111985
Change-Id: I038a533ccbc5018cd125a49e70320a36b5aa4d31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2360816
Commit-Queue: Erik Chen <erikchen@chromium.org>
Reviewed-by: dpapad <dpapad@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800764}

chrome/browser/resources/chromeos/bluetooth_pairing_dialog/BUILD.gn

@@ -24,6 +24,8 @@ if (optimize_webui) {
       ":unpak",
       "../../../../../ui/webui/resources:modulize",
     ]
+
+    excludes = [ "chrome://resources/js/cr.m.js" ]
   }
 
   unpak("unpak") {

chrome/test/data/webui/icon_test.html

@@ -18,7 +18,7 @@ function testGetFaviconForPageURL() {
       '&allow_google_server_fallback=0") ' +
       window.devicePixelRatio + 'x)';
 
-  var isDesktop = cr.isMac || cr.isChromeOS || cr.isWindows || cr.isLinux;
+  var isDesktop = cr.isMac || cr.isChromeOS || cr.isWindows || cr.isLinux || cr.isLacros;
   var expected = isDesktop ? expectedDesktop : expectedOther;
   assertEquals(expected, cr.icon.getFaviconForPageURL(url));
 }
@@ -35,7 +35,7 @@ function testGetFavicon() {
       encodeURIComponent('http://foo.com/foo.ico')+'") ' +
       window.devicePixelRatio + 'x)';
 
-  var isDesktop = cr.isMac || cr.isChromeOS || cr.isWindows || cr.isLinux;
+  var isDesktop = cr.isMac || cr.isChromeOS || cr.isWindows || cr.isLinux || cr.isLacros;
   var expected = isDesktop ? expectedDesktop : expectedOther;
   assertEquals(expected, cr.icon.getFavicon(url));
 }

ui/webui/resources/js/cr.js

@@ -436,9 +436,26 @@ var cr = cr || function(global) {
       return /Win/.test(navigator.platform);
     },
 
-    /** Whether this is on chromeOS or not. */
+    /** Whether this is the ChromeOS/ash web browser. */
     get isChromeOS() {
-      return /CrOS/.test(navigator.userAgent);
+      let returnValue = false;
+      // TODO(https://crbug.com/1118190): grit conditionals do not work in many
+      // WebUI tests.
+      // <if expr="chromeos">
+      returnValue = true;
+      // </if>
+      return returnValue;
+    },
+
+    /** Whether this is the ChromeOS/Lacros web browser. */
+    get isLacros() {
+      let returnValue = false;
+      // TODO(https://crbug.com/1118190): grit conditionals do not work in many
+      // WebUI tests.
+      // <if expr="lacros">
+      returnValue = true;
+      // </if>
+      return returnValue;
     },
 
     /** Whether this is on vanilla Linux (not chromeOS). */

ui/webui/resources/js/cr.m.js

@@ -184,8 +184,23 @@ export const isMac = /Mac/.test(navigator.platform);
 /** Whether this is on the Windows platform or not. */
 export const isWindows = /Win/.test(navigator.platform);
 
-/** Whether this is on chromeOS or not. */
-export const isChromeOS = /CrOS/.test(navigator.userAgent);
+/** Whether this is the ChromeOS/ash web browser. */
+export const isChromeOS = (() => {
+  let returnValue = false;
+  // <if expr="chromeos">
+  returnValue = true;
+  // </if>
+  return returnValue;
+})();
+
+/** Whether this is the ChromeOS/Lacros web browser. */
+export const isLacros = (() => {
+  let returnValue = false;
+  // <if expr="lacros">
+  returnValue = true;
+  // </if>
+  return returnValue;
+})();
 
 /** Whether this is on vanilla Linux (not chromeOS). */
 export const isLinux = /Linux/.test(navigator.userAgent);

ui/webui/resources/js/cr/ui/context_menu_handler.js

@@ -162,7 +162,8 @@ cr.define('cr.ui', function() {
         case 'mousedown':
           if (!this.menu.contains(e.target)) {
             this.hideMenu();
-            if (e.button === 0 /* Left button */ && (cr.isLinux || cr.isMac)) {
+            if (e.button === 0 /* Left button */ &&
+                (cr.isLinux || cr.isMac || cr.isLacros)) {
               // Emulate Mac and Linux, which swallow native 'mousedown' events
               // that close menus.
               e.preventDefault();

ui/webui/resources/js/icon.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// #import {isChromeOS, isIOS, isLinux, isMac, isWindows} from './cr.m.js';
+// #import {isAndroid, isIOS} from './cr.m.js';
 
 cr.define('cr.icon', function() {
   /**
@@ -16,7 +16,7 @@ cr.define('cr.icon', function() {
       // supports SCALE_FACTOR_100P on all non-iOS platforms.
       supportedScaleFactors.push(1);
     }
-    if (cr.isMac || cr.isChromeOS || cr.isWindows || cr.isLinux) {
+    if (!cr.isIOS && !cr.isAndroid) {
       // All desktop platforms support zooming which also updates the renderer's
       // device scale factors (a.k.a devicePixelRatio), and these platforms have
       // high DPI assets for 2x.  Let the renderer pick the closest image for

ui/webui/resources/tools/js_modulizer.gni

@@ -12,6 +12,7 @@ common_namespace_rewrites = [
   "cr.isAndroid|isAndroid",
   "cr.isChromeOS|isChromeOS",
   "cr.isIOS|isIOS",
+  "cr.isLacros|isLacros",
   "cr.isLinux|isLinux",
   "cr.isMac|isMac",
   "cr.isWindows|isWindows",

ui/webui/resources/webui_resources.grd

@@ -295,9 +295,11 @@ without changes to the corresponding grd file. -->
                  file="js/promise_resolver.js" type="chrome_html" />
 
       <structure name="IDR_WEBUI_JS_CR"
-                 file="js/cr.js" type="chrome_html" />
+                 file="js/cr.js" type="chrome_html"
+                 preprocess="true" />
       <structure name="IDR_WEBUI_JS_CR_M_JS"
-                 file="js/cr.m.js" type="chrome_html" />
+                 file="js/cr.m.js" type="chrome_html"
+                 preprocess="true" />
       <structure name="IDR_WEBUI_JS_CR_EVENT_TARGET"
                  file="js/cr/event_target.js" type="chrome_html" />
       <structure name="IDR_WEBUI_JS_CR_UI"