diff --git a/core/modules/tracker/src/Tests/TrackerWithoutCommentTest.php b/core/modules/tracker/src/Tests/TrackerWithoutCommentTest.php
new file mode 100644
index 0000000..dfc5283
--- /dev/null
+++ b/core/modules/tracker/src/Tests/TrackerWithoutCommentTest.php
@@ -0,0 +1,296 @@
+<?php
+
+namespace Drupal\tracker\Tests;
+
+use Drupal\comment\CommentInterface;
+use Drupal\comment\Tests\CommentTestTrait;
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\node\Entity\Node;
+use Drupal\simpletest\WebTestBase;
+use Drupal\system\Tests\Cache\AssertPageCacheContextsAndTagsTrait;
+
+/**
+ * Create and delete nodes and check for their display in the tracker listings.
+ *
+ * @group tracker
+ */
+class TrackerWithoutCommentTest extends WebTestBase {
+
+  use AssertPageCacheContextsAndTagsTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = ['block', 'tracker', 'history', 'node_test'];
+
+  /**
+   * The main user for testing.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $user;
+
+  /**
+   * A second user that will 'create' comments and nodes.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $otherUser;
+
+  protected function setUp() {
+    parent::setUp();
+
+    $this->drupalCreateContentType(['type' => 'page', 'name' => 'Basic page']);
+
+    $permissions = ['create page content'];
+    $this->user = $this->drupalCreateUser($permissions);
+    $this->otherUser = $this->drupalCreateUser($permissions);
+    user_role_grant_permissions(AccountInterface::ANONYMOUS_ROLE, [
+      'access content',
+      'access user profiles',
+    ]);
+    $this->drupalPlaceBlock('local_tasks_block', ['id' => 'page_tabs_block']);
+    $this->drupalPlaceBlock('local_actions_block', ['id' => 'page_actions_block']);
+  }
+
+  /**
+   * Tests for the presence of nodes on the global tracker listing.
+   */
+  public function testTrackerAll() {
+    $this->drupalLogin($this->user);
+
+    $unpublished = $this->drupalCreateNode([
+      'title' => $this->randomMachineName(8),
+      'status' => 0,
+    ]);
+    $published = $this->drupalCreateNode([
+      'title' => $this->randomMachineName(8),
+      'status' => 1,
+    ]);
+
+    $this->drupalGet('activity');
+    $this->assertNoText($unpublished->label(), 'Unpublished node does not show up in the tracker listing.');
+    $this->assertText($published->label(), 'Published node shows up in the tracker listing.');
+    $this->assertLink(t('My recent content'), 0, 'User tab shows up on the global tracker page.');
+
+    // Assert cache contexts, specifically the pager and node access contexts.
+    $this->assertCacheContexts(['languages:language_interface', 'route', 'theme', 'url.query_args:' . MainContentViewSubscriber::WRAPPER_FORMAT, 'url.query_args.pagers:0', 'user.node_grants:view', 'user']);
+    // Assert cache tags for the action/tabs blocks, visible node, and node list
+    // cache tag.
+    $expected_tags = Cache::mergeTags($published->getCacheTags(), $published->getOwner()->getCacheTags());
+    // Because the 'user.permissions' cache context is being optimized away.
+    $role_tags = [];
+    foreach ($this->user->getRoles() as $rid) {
+      $role_tags[] = "config:user.role.$rid";
+    }
+    $expected_tags = Cache::mergeTags($expected_tags, $role_tags);
+    $block_tags = [
+      'block_view',
+      'config:block.block.page_actions_block',
+      'config:block.block.page_tabs_block',
+      'config:block_list',
+    ];
+    $expected_tags = Cache::mergeTags($expected_tags, $block_tags);
+    $additional_tags = [
+      'node_list',
+      'rendered',
+    ];
+    $expected_tags = Cache::mergeTags($expected_tags, $additional_tags);
+    $this->assertCacheTags($expected_tags);
+
+    // Delete a node and ensure it no longer appears on the tracker.
+    $published->delete();
+    $this->drupalGet('activity');
+    $this->assertNoText($published->label(), 'Deleted node does not show up in the tracker listing.');
+  }
+
+  /**
+   * Tests for the presence of nodes on a user's tracker listing.
+   */
+  public function testTrackerUser() {
+    $this->drupalLogin($this->user);
+
+    $unpublished = $this->drupalCreateNode([
+      'title' => $this->randomMachineName(8),
+      'uid' => $this->user->id(),
+      'status' => 0,
+    ]);
+    $my_published = $this->drupalCreateNode([
+      'title' => $this->randomMachineName(8),
+      'uid' => $this->user->id(),
+      'status' => 1,
+    ]);
+
+    $this->drupalGet('user/' . $this->user->id() . '/activity');
+    $this->assertNoText($unpublished->label(), "Unpublished nodes do not show up in the user's tracker listing.");
+    $this->assertText($my_published->label(), "Published nodes show up in the user's tracker listing.");
+
+    // Assert cache contexts.
+    $this->assertCacheContexts(['languages:language_interface', 'route', 'theme', 'url.query_args:' . MainContentViewSubscriber::WRAPPER_FORMAT, 'url.query_args.pagers:0', 'user', 'user.node_grants:view']);
+    // Assert cache tags for the visible nodes (including owners) and node list
+    // cache tag.
+    $expected_tags = Cache::mergeTags($my_published->getCacheTags(), $my_published->getOwner()->getCacheTags());
+    // Because the 'user.permissions' cache context is being optimized away.
+    $role_tags = [];
+    foreach ($this->user->getRoles() as $rid) {
+      $role_tags[] = "config:user.role.$rid";
+    }
+    $expected_tags = Cache::mergeTags($expected_tags, $role_tags);
+    $block_tags = [
+      'block_view',
+      'config:block.block.page_actions_block',
+      'config:block.block.page_tabs_block',
+      'config:block_list',
+    ];
+    $expected_tags = Cache::mergeTags($expected_tags, $block_tags);
+    $additional_tags = [
+      'node_list',
+      'rendered',
+    ];
+    $expected_tags = Cache::mergeTags($expected_tags, $additional_tags);
+
+    $this->assertCacheTags($expected_tags);
+    $this->assertCacheContexts(['languages:language_interface', 'route', 'theme', 'url.query_args:' . MainContentViewSubscriber::WRAPPER_FORMAT, 'url.query_args.pagers:0', 'user', 'user.node_grants:view']);
+
+    $this->assertLink($my_published->label());
+    $this->assertNoLink($unpublished->label());
+    // Verify that title and tab title have been set correctly.
+    $this->assertText('Activity', 'The user activity tab has the name "Activity".');
+    $this->assertTitle(t('@name | @site', ['@name' => $this->user->getUsername(), '@site' => $this->config('system.site')->get('name')]), 'The user tracker page has the correct page title.');
+
+    // Test escaping of title on user's tracker tab.
+    \Drupal::service('module_installer')->install(['user_hooks_test']);
+    Cache::invalidateTags(['rendered']);
+    \Drupal::state()->set('user_hooks_test_user_format_name_alter', TRUE);
+    $this->drupalGet('user/' . $this->user->id() . '/activity');
+    $this->assertEscaped('<em>' . $this->user->id() . '</em>');
+
+    \Drupal::state()->set('user_hooks_test_user_format_name_alter_safe', TRUE);
+    Cache::invalidateTags(['rendered']);
+    $this->drupalGet('user/' . $this->user->id() . '/activity');
+    $this->assertNoEscaped('<em>' . $this->user->id() . '</em>');
+    $this->assertRaw('<em>' . $this->user->id() . '</em>');
+  }
+
+  /**
+   * Tests the metadata for the "new"/"updated" indicators.
+   */
+  public function testTrackerHistoryMetadata() {
+    $this->drupalLogin($this->user);
+
+    // Create a page node.
+    $edit = [
+      'title' => $this->randomMachineName(8),
+    ];
+    $node = $this->drupalCreateNode($edit);
+
+    // Verify that the history metadata is present.
+    $this->drupalGet('activity');
+    $this->assertHistoryMetadata($node->id(), $node->getChangedTime());
+    $this->drupalGet('activity/' . $this->user->id());
+    $this->assertHistoryMetadata($node->id(), $node->getChangedTime());
+    $this->drupalGet('user/' . $this->user->id() . '/activity');
+    $this->assertHistoryMetadata($node->id(), $node->getChangedTime());
+  }
+
+  /**
+   * Tests that existing nodes are indexed by cron.
+   */
+  public function testTrackerCronIndexing() {
+    $this->drupalLogin($this->user);
+
+    // Create 3 nodes.
+    $edits = [];
+    $nodes = [];
+    for ($i = 1; $i <= 3; $i++) {
+      $edits[$i] = [
+        'title' => $this->randomMachineName(),
+      ];
+      $nodes[$i] = $this->drupalCreateNode($edits[$i]);
+    }
+
+    // Start indexing backwards from node 3.
+    \Drupal::state()->set('tracker.index_nid', 3);
+
+    // Clear the current tracker tables and rebuild them.
+    db_delete('tracker_node')
+      ->execute();
+    db_delete('tracker_user')
+      ->execute();
+    tracker_cron();
+
+    $this->drupalLogin($this->user);
+
+    // Fetch the user's tracker.
+    $this->drupalGet('activity/' . $this->user->id());
+
+    // Assert that all node titles are displayed.
+    foreach ($nodes as $i => $node) {
+      $this->assertText($node->label(), format_string('Node @i is displayed on the tracker listing pages.', ['@i' => $i]));
+    }
+
+    // Fetch the site-wide tracker.
+    $this->drupalGet('activity');
+
+    // Assert that all node titles are displayed.
+    foreach ($nodes as $i => $node) {
+      $this->assertText($node->label(), format_string('Node @i is displayed on the tracker listing pages.', ['@i' => $i]));
+    }
+  }
+
+  /**
+   * Tests that publish/unpublish works at admin/content/node.
+   */
+  public function testTrackerAdminUnpublish() {
+    \Drupal::service('module_installer')->install(['views']);
+    \Drupal::service('router.builder')->rebuild();
+    $admin_user = $this->drupalCreateUser(['access content overview', 'administer nodes', 'bypass node access']);
+    $this->drupalLogin($admin_user);
+
+    $node = $this->drupalCreateNode([
+      'title' => $this->randomMachineName(),
+    ]);
+
+    // Assert that the node is displayed.
+    $this->drupalGet('activity');
+    $this->assertText($node->label(), 'A node is displayed on the tracker listing pages.');
+
+    // Unpublish the node and ensure that it's no longer displayed.
+    $edit = [
+      'action' => 'node_unpublish_action',
+      'node_bulk_form[0]' => $node->id(),
+    ];
+    $this->drupalPostForm('admin/content', $edit, t('Apply to selected items'));
+
+    $this->drupalGet('activity');
+    $this->assertText(t('No content available.'), 'A node is displayed on the tracker listing pages.');
+  }
+
+  /**
+   * Passes if the appropriate history metadata exists.
+   *
+   * Verify the data-history-node-id, data-history-node-timestamp attribute,
+   * which is used by the drupal.tracker-history library to add the appropriate
+   * "new" and "updated" indicators, as well as the "x new" replies link to the
+   * tracker. We do this in JavaScript to prevent breaking the render cache.
+   *
+   * @param int $node_id
+   *   A node ID, that must exist as a data-history-node-id attribute
+   * @param int $node_timestamp
+   *   A node timestamp, that must exist as a data-history-node-timestamp
+   *   attribute.
+   * @param bool $library_is_present
+   *   Whether the drupal.tracker-history library should be present or not.
+   */
+  public function assertHistoryMetadata($node_id, $node_timestamp, $library_is_present = TRUE) {
+    $settings = $this->getDrupalSettings();
+    $this->assertIdentical($library_is_present, isset($settings['ajaxPageState']) && in_array('tracker/history', explode(',', $settings['ajaxPageState']['libraries'])), 'drupal.tracker-history library is present.');
+    $this->assertIdentical(1, count($this->xpath('//table/tbody/tr/td[@data-history-node-id="' . $node_id . '" and @data-history-node-timestamp="' . $node_timestamp . '"]')), 'Tracker table cell contains the data-history-node-id and data-history-node-timestamp attributes for the node.');
+  }
+
+}
diff --git a/core/modules/tracker/tests/src/Functional/TrackerNodeAccessTest.php b/core/modules/tracker/tests/src/Functional/TrackerNodeAccessTest.php
index 2b320ae..4dd32df 100644
--- a/core/modules/tracker/tests/src/Functional/TrackerNodeAccessTest.php
+++ b/core/modules/tracker/tests/src/Functional/TrackerNodeAccessTest.php
@@ -4,6 +4,7 @@
 
 use Drupal\comment\Plugin\Field\FieldType\CommentItemInterface;
 use Drupal\comment\Tests\CommentTestTrait;
+use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\node\Entity\NodeType;
 use Drupal\Tests\BrowserTestBase;
 
@@ -61,6 +62,8 @@ public function testTrackerNodeAccess() {
     $this->drupalGet('user/' . $access_user->id() . '/activity');
     $this->assertText($private_node->getTitle(), 'Private node is visible to user with private access.');
     $this->assertText($public_node->getTitle(), 'Public node is visible to user with private access.');
+    // Comments column displayed.
+    $this->assertSession()->pageTextContains('Comments');
 
     // User without access should not see private node.
     $this->drupalLogin($no_access_user);
@@ -70,6 +73,23 @@ public function testTrackerNodeAccess() {
     $this->drupalGet('user/' . $access_user->id() . '/activity');
     $this->assertNoText($private_node->getTitle(), 'Private node is not visible to user without private access.');
     $this->assertText($public_node->getTitle(), 'Public node is visible to user without private access.');
+
+    // Ensure module pages works when comment module uninstalled.
+    $field = FieldStorageConfig::loadByName('node', 'comment');
+    $field->delete();
+    field_purge_batch(10);
+    /** @var \Drupal\Core\Extension\ModuleInstallerInterface $service */
+    $service = \Drupal::service('module_installer');
+    $service->uninstall(['comment']);
+    $this->drupalLogin($access_user);
+    $this->drupalGet('activity');
+    $this->assertSession()->pageTextContains($private_node->getTitle());
+    // Comments column hidden.
+    $this->assertSession()->pageTextNotContains('Comments');
+    $this->drupalGet('user/' . $access_user->id() . '/activity');
+    $this->assertSession()->pageTextContains($private_node->getTitle());
+    // Comments column hidden.
+    $this->assertSession()->pageTextNotContains('Comments');
   }
 
 }
diff --git a/core/modules/tracker/tracker.info.yml b/core/modules/tracker/tracker.info.yml
index 79d179d..2a62162 100644
--- a/core/modules/tracker/tracker.info.yml
+++ b/core/modules/tracker/tracker.info.yml
@@ -3,7 +3,6 @@ type: module
 description: 'Enables tracking of recent content for users.'
 dependencies:
   - node
-  - comment
 package: Core
 version: VERSION
 core: 8.x
diff --git a/core/modules/tracker/tracker.module b/core/modules/tracker/tracker.module
index dbde704..d45c53d 100644
--- a/core/modules/tracker/tracker.module
+++ b/core/modules/tracker/tracker.module
@@ -93,26 +93,27 @@ function tracker_cron() {
       // Get unique user IDs via entityQueryAggregate because it's the easiest
       // database agnostic way. We don't actually care about the comments here
       // so don't add an aggregate field.
-      $result = \Drupal::entityQueryAggregate('comment')
-        ->condition('entity_type', 'node')
-        ->condition('entity_id', $node->id())
-        ->condition('uid', $node->getOwnerId(), '<>')
-        ->condition('status', CommentInterface::PUBLISHED)
-        ->groupBy('uid')
-        ->execute();
-      if ($result) {
-        $query = db_insert('tracker_user');
-        foreach ($result as $row) {
-          $query->fields([
-            'uid' => $row['uid'],
-            'nid' => $nid,
-            'published' => CommentInterface::PUBLISHED,
-            'changed' => $changed,
-          ]);
+      if (\Drupal::moduleHandler()->moduleExists('comment')) {
+        $result = \Drupal::entityQueryAggregate('comment')
+          ->condition('entity_type', 'node')
+          ->condition('entity_id', $node->id())
+          ->condition('uid', $node->getOwnerId(), '<>')
+          ->condition('status', CommentInterface::PUBLISHED)
+          ->groupBy('uid')
+          ->execute();
+        if ($result) {
+          $query = db_insert('tracker_user');
+          foreach ($result as $row) {
+            $query->fields([
+              'uid' => $row['uid'],
+              'nid' => $nid,
+              'published' => CommentInterface::PUBLISHED,
+              'changed' => $changed,
+            ]);
+          }
+          $query->execute();
         }
-        $query->execute();
       }
-
       // Note that we have indexed at least one node.
       $last_nid = $nid;
 
@@ -293,9 +294,11 @@ function _tracker_add($nid, $uid, $changed) {
  */
 function _tracker_calculate_changed($node) {
   $changed = $node->getChangedTime();
-  $latest_comment = \Drupal::service('comment.statistics')->read([$node], 'node', FALSE);
-  if ($latest_comment && $latest_comment->last_comment_timestamp > $changed) {
-    $changed = $latest_comment->last_comment_timestamp;
+  if (\Drupal::hasService('comment.statistics')) {
+    $latest_comment = \Drupal::service('comment.statistics')->read([$node], 'node', FALSE);
+    if ($latest_comment && $latest_comment->last_comment_timestamp > $changed) {
+      $changed = $latest_comment->last_comment_timestamp;
+    }
   }
   return $changed;
 }
diff --git a/core/modules/tracker/tracker.pages.inc b/core/modules/tracker/tracker.pages.inc
index 76a775f..4c40be5 100644
--- a/core/modules/tracker/tracker.pages.inc
+++ b/core/modules/tracker/tracker.pages.inc
@@ -48,32 +48,34 @@ function tracker_page($account = NULL) {
 
   $cache_tags = [];
   $rows = [];
+  $has_comment_stats_service = \Drupal::hasService('comment.statistics');
   if (!empty($tracker_data)) {
     // Load nodes into an array with the same order as $tracker_data.
     $nodes = Node::loadMultiple(array_keys($tracker_data));
 
     // Enrich the node data.
-    $result = \Drupal::service('comment.statistics')->read($nodes, 'node', FALSE);
-    foreach ($result as $statistics) {
-      // The node ID may not be unique; there can be multiple comment fields.
-      // Make comment_count the total of all comments.
-      $nid = $statistics->entity_id;
-      if (empty($nodes[$nid]->comment_count)
-          || !is_numeric($nodes[$nid]->comment_count)) {
-        $nodes[$nid]->comment_count = $statistics->comment_count;
-      }
-      else {
-        $nodes[$nid]->comment_count += $statistics->comment_count;
-      }
-      // Make the last comment timestamp reflect the latest comment.
-      if (!isset($nodes[$nid]->last_comment_timestamp)) {
-        $nodes[$nid]->last_comment_timestamp = $statistics->last_comment_timestamp;
-      }
-      else {
-        $nodes[$nid]->last_comment_timestamp = max($nodes[$nid]->last_comment_timestamp, $statistics->last_comment_timestamp);
+    if ($has_comment_stats_service) {
+      $result = \Drupal::service('comment.statistics')
+        ->read($nodes, 'node', FALSE);
+      foreach ($result as $statistics) {
+        // The node ID may not be unique; there can be multiple comment fields.
+        // Make comment_count the total of all comments.
+        $nid = $statistics->entity_id;
+        if (empty($nodes[$nid]->comment_count) || !is_numeric($nodes[$nid]->comment_count)) {
+          $nodes[$nid]->comment_count = $statistics->comment_count;
+        }
+        else {
+          $nodes[$nid]->comment_count += $statistics->comment_count;
+        }
+        // Make the last comment timestamp reflect the latest comment.
+        if (!isset($nodes[$nid]->last_comment_timestamp)) {
+          $nodes[$nid]->last_comment_timestamp = $statistics->last_comment_timestamp;
+        }
+        else {
+          $nodes[$nid]->last_comment_timestamp = max($nodes[$nid]->last_comment_timestamp, $statistics->last_comment_timestamp);
+        }
       }
     }
-
     // Display the data.
     foreach ($nodes as $node) {
       // Set the last activity time from tracker data. This also takes into
@@ -103,18 +105,19 @@ function tracker_page($account = NULL) {
             '#account' => $node->getOwner(),
           ],
         ],
-        'comments' => [
+      ];
+      if ($has_comment_stats_service) {
+        $row['comments'] = [
           'class' => ['comments'],
           'data' => $comments,
           'data-history-node-last-comment-timestamp' => $node->last_comment_timestamp,
-        ],
-        'last updated' => [
-          'data' => t('@time ago', [
-            '@time' => \Drupal::service('date.formatter')->formatTimeDiffSince($node->last_activity),
-          ]),
-        ],
+        ];
+      }
+      $row['last updated'] = [
+        'data' => t('@time ago', [
+          '@time' => \Drupal::service('date.formatter')->formatTimeDiffSince($node->last_activity),
+        ])
       ];
-
       $rows[] = $row;
 
       // Add node and node owner to cache tags.
@@ -130,7 +133,7 @@ function tracker_page($account = NULL) {
 
   $page['tracker'] = [
     '#rows' => $rows,
-    '#header' => [t('Type'), t('Title'), t('Author'), t('Comments'), t('Last updated')],
+    '#header' => $has_comment_stats_service ? [t('Type'), t('Title'), t('Author'), t('Comments'), t('Last updated')] : [t('Type'), t('Title'), t('Author'), t('Last updated')],
     '#type' => 'table',
     '#empty' => t('No content available.'),
   ];