plugin_vm: allow uninstallation when policy is disabled

If the policy is disabled, the user still needs a way to cleanup the vm
from their disk. This change allows them access to the plugin vm subpage
as long as either the policy is enabled, or there is a vm on disk.

Note: It is not enough to simply delete the vm for the user, as the
policy change could be accidental or temporary.

Bug: 1023256
Change-Id: Id1cfae86061c8f7e1a0b771165833e412009edbe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026511
Commit-Queue: Julian Watson <juwa@google.com>
Auto-Submit: Julian Watson <juwa@google.com>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738029}

chrome/browser/resources/settings/chromeos/plugin_vm_page/plugin_vm_page.html

@@ -30,15 +30,21 @@
             </div>
           </div>
           <template is="dom-if" if="[[prefs.plugin_vm.image_exists.value]]">
-            <cr-icon-button class="subpage-arrow"
+            <cr-icon-button id="navigate-to-subpage"
+                class="subpage-arrow"
                 aria-label="i18n{pluginVmPageLabel}"
                 aria-describedby="secondaryText"
                 aria-roledescription="$i18n{subpageArrowRoleDescription}">
             </cr-icon-button>
           </template>
           <template is="dom-if" if="[[!prefs.plugin_vm.image_exists.value]]">
+            <template is="dom-if" if="[[!allowPluginVm_]]" restamp>
+              <cr-policy-indicator indicator-type="userPolicy">
+              </cr-policy-indicator>
+            </template>
             <div class="separator"></div>
             <cr-button id="enable"
+                disabled="[[!allowPluginVm_]]"
                 on-click="onEnableClick_"
                 aria-describedby="secondaryText">
               $i18n{pluginVmPageEnable}

chrome/browser/resources/settings/chromeos/plugin_vm_page/plugin_vm_page.js

@@ -19,6 +19,9 @@ Polymer({
       notify: true,
     },
 
+    /** @private */
+    allowPluginVm_: Boolean,
+
     /** @private {!Map<string, string>} */
     focusConfig_: {
       type: Object,
@@ -35,6 +38,12 @@ Polymer({
     },
   },
 
+  /** @override */
+  attached: function() {
+    this.allowPluginVm_ = loadTimeData.valueExists('allowPluginVm') &&
+        loadTimeData.getBoolean('allowPluginVm');
+  },
+
   /**
    * @param {!Event} event
    * @private

chrome/browser/ui/webui/settings/chromeos/os_settings_ui.cc

@@ -26,6 +26,7 @@
 #include "chrome/browser/chromeos/login/demo_mode/demo_session.h"
 #include "chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h"
 #include "chrome/browser/chromeos/multidevice_setup/multidevice_setup_client_factory.h"
+#include "chrome/browser/chromeos/plugin_vm/plugin_vm_pref_names.h"
 #include "chrome/browser/chromeos/plugin_vm/plugin_vm_util.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/signin/identity_manager_factory.h"
@@ -298,7 +299,14 @@ void OSSettingsUI::InitOSWebUIHandlers(content::WebUIDataSource* html_source) {
   web_ui()->AddMessageHandler(
       std::make_unique<chromeos::settings::WallpaperHandler>(web_ui()));
 
-  if (plugin_vm::IsPluginVmAllowedForProfile(profile)) {
+  // If |!allow_plugin_vm| we still want to |show_plugin_vm| if the VM image is
+  // on disk, so that users are still able to delete the image at will.
+  const bool allow_plugin_vm = plugin_vm::IsPluginVmAllowedForProfile(profile);
+  const bool show_plugin_vm =
+      allow_plugin_vm ||
+      profile->GetPrefs()->GetBoolean(plugin_vm::prefs::kPluginVmImageExists);
+
+  if (show_plugin_vm) {
     web_ui()->AddMessageHandler(
         std::make_unique<chromeos::settings::PluginVmHandler>(profile));
   }
@@ -392,8 +400,8 @@ void OSSettingsUI::InitOSWebUIHandlers(content::WebUIDataSource* html_source) {
   html_source->AddBoolean(
       "allowCrostini", crostini::CrostiniFeatures::Get()->IsUIAllowed(profile));
 
-  html_source->AddBoolean("showPluginVm",
-                          plugin_vm::IsPluginVmAllowedForProfile(profile));
+  html_source->AddBoolean("allowPluginVm", allow_plugin_vm);
+  html_source->AddBoolean("showPluginVm", show_plugin_vm);
 
   html_source->AddBoolean("isDemoSession",
                           chromeos::DemoSession::IsDeviceInDemoMode());

chrome/test/data/webui/settings/chromeos/plugin_vm_page_test.js

@@ -53,7 +53,6 @@ suite('PluginVmPage', function() {
     pluginVmBrowserProxy = new TestPluginVmBrowserProxy();
     settings.PluginVmBrowserProxyImpl.instance_ = pluginVmBrowserProxy;
     PolymerTest.clearBody();
-    page = document.createElement('settings-plugin-vm-page');
 
     routes = [];
 
@@ -72,41 +71,55 @@ suite('PluginVmPage', function() {
     settings.routes = preTestSettingsRoutes;
   });
 
-  test('ImageExistsLink', function() {
-    page.prefs = {
-      plugin_vm: {
-        image_exists: {value: true},
-      }
-    };
+  function setUpPluginVmPage({allowedByPolicy, vmImageExists}) {
+    loadTimeData.overrideValues({allowPluginVm: allowedByPolicy});
+
+    page = document.createElement('settings-plugin-vm-page');
+    page.prefs = {plugin_vm: {image_exists: {value: vmImageExists}}};
     document.body.appendChild(page);
+
     Polymer.dom.flush();
+  }
+
+  test('PolicyEnabledAndImageExists', function() {
+    setUpPluginVmPage({allowedByPolicy: true, vmImageExists: true});
 
-    const button = page.$$('cr-icon-button');
-    assertTrue(!!button);
+    assertEquals(page.$$('#enable'), null);
 
     assertDeepEquals(routes, []);
-    button.click();
+    page.$$('#navigate-to-subpage').click();
     assertDeepEquals(routes, ['TEST_PLUGIN_VM_DETAILS_ROUTE']);
   });
 
-  test('ImageDoesntExist', function() {
-    page.prefs = {
-      plugin_vm: {
-        image_exists: {value: false},
-      }
-    };
-    document.body.appendChild(page);
-    Polymer.dom.flush();
+  test('PolicyEnabledAndImageDoesntExist', function() {
+    setUpPluginVmPage({allowedByPolicy: true, vmImageExists: false});
 
-    const button = page.$$('cr-button');
-    assertTrue(!!button);
+    assertEquals(page.$$('#navigate-to-subpage'), null);
 
     assertEquals(
         0, pluginVmBrowserProxy.getCallCount('requestPluginVmInstallerView'));
-    button.click();
+    page.$$('#enable').click();
     assertEquals(
         1, pluginVmBrowserProxy.getCallCount('requestPluginVmInstallerView'));
   });
+
+  test('PolicyDisabledAndImageExists', function() {
+    setUpPluginVmPage({allowedByPolicy: false, vmImageExists: true});
+
+    assertEquals(page.$$('#enable'), null);
+
+    assertDeepEquals(routes, []);
+    page.$$('#navigate-to-subpage').click();
+    assertDeepEquals(routes, ['TEST_PLUGIN_VM_DETAILS_ROUTE']);
+  });
+
+  test('PolicyDisabledAndImageDoesntExist', function() {
+    setUpPluginVmPage({allowedByPolicy: false, vmImageExists: false});
+
+    assertEquals(page.$$('#navigate-to-subpage'), null);
+
+    assertTrue(page.$$('#enable').disabled);
+  });
 });
 
 suite('Details', function() {