diff --git a/core/includes/common.inc b/core/includes/common.inc
index da65525..1a50e38 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -913,6 +913,10 @@ function drupal_set_time_limit($time_limit) {
 /**
  * Returns the path to a system item (module, theme, etc.).
  *
+ * This function should only be used when including a file containing PHP code;
+ * the 'module://', 'profile://' and 'theme://' stream wrappers should be used
+ * for other use cases.
+ *
  * @param $type
  *   The type of the item; one of 'core', 'profile', 'module', 'theme', or
  *   'theme_engine'.
diff --git a/core/lib/Drupal/Core/StreamWrapper/LocalStream.php b/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
index 937953f..dbc7fcb 100644
--- a/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
+++ b/core/lib/Drupal/Core/StreamWrapper/LocalStream.php
@@ -87,10 +87,17 @@ protected function getTarget($uri = NULL) {
       $uri = $this->uri;
     }
 
-    list(, $target) = explode('://', $uri, 2);
+    $uri_parts = explode('://', $uri, 2);
+    if (count($uri_parts) === 1) {
+      // The delimiter ('://') was not found in $uri, malformed $uri passed.
+      throw new \InvalidArgumentException('Malformed $uri parameter passed: %s', $uri);
+    }
+    else {
+      list(, $target) = $uri_parts;
 
-    // Remove erroneous leading or trailing, forward-slashes and backslashes.
-    return trim($target, '\/');
+      // Remove erroneous leading or trailing, forward-slashes and backslashes.
+      return trim($target, '\/');
+    }
   }
 
   /**
diff --git a/core/lib/Drupal/Core/StreamWrapper/ModuleStream.php b/core/lib/Drupal/Core/StreamWrapper/ModuleStream.php
new file mode 100644
index 0000000..9021ae3
--- /dev/null
+++ b/core/lib/Drupal/Core/StreamWrapper/ModuleStream.php
@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\StreamWrapper\ModuleStream.
+ */
+
+namespace Drupal\Core\StreamWrapper;
+
+/**
+ * Defines a read-only Drupal stream wrapper base class for modules.
+ *
+ * This class extends the complete stream wrapper implementation in LocalStream.
+ * URIs such as "module://system" are expanded to a normal filesystem path
+ * such as "modules/system" and then PHP filesystem functions are
+ * invoked.
+ */
+class ModuleStream extends SystemStream {
+
+  /**
+   * Get the module name of the current URI.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return string
+   *   The extension name.
+   */
+  public function getOwnerName($uri = NULL) {
+    $name = parent::getOwnerName($uri);
+    return \Drupal::moduleHandler()->moduleExists($name) ? $name : FALSE;
+  }
+
+  /**
+   * Gets the module's directory path.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return string
+   *   String specifying the path.
+   */
+  public function getDirectoryPath($uri = NULL) {
+    return drupal_get_path('module', $this->getOwnerName($uri));
+  }
+}
diff --git a/core/lib/Drupal/Core/StreamWrapper/ProfileStream.php b/core/lib/Drupal/Core/StreamWrapper/ProfileStream.php
new file mode 100644
index 0000000..bf2cdfc
--- /dev/null
+++ b/core/lib/Drupal/Core/StreamWrapper/ProfileStream.php
@@ -0,0 +1,49 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\StreamWrapper\ProfileStream.
+ */
+
+namespace Drupal\Core\StreamWrapper;
+
+/**
+ * Defines a read-only Drupal stream wrapper base class for profiles.
+ *
+ * This class extends the complete stream wrapper implementation in LocalStream.
+ * URIs such as "profile://standard" are expanded to a normal filesystem path
+ * such as "profiles/standard" and then PHP filesystem functions are invoked.
+ *
+ * Specifying "profile://current" will return a stream for the currently
+ * installed profile.
+ */
+class ProfileStream extends SystemStream {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getOwnerName($uri = NULL) {
+    $name = parent::getOwnerName($uri);
+    $current = drupal_get_profile();
+    switch ($name) {
+      case 'current':
+      case $current:
+        return $current;
+      default:
+        return !is_null(drupal_get_filename('profile', $name)) ? $name : FALSE;
+    }
+  }
+
+  /**
+   * Gets the profile's directory path.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return string
+   *   String specifying the path.
+   */
+  public function getDirectoryPath($uri = NULL) {
+    return drupal_get_path('profile', $this->getOwnerName($uri));
+  }
+}
diff --git a/core/lib/Drupal/Core/StreamWrapper/SystemStream.php b/core/lib/Drupal/Core/StreamWrapper/SystemStream.php
new file mode 100644
index 0000000..07e365b
--- /dev/null
+++ b/core/lib/Drupal/Core/StreamWrapper/SystemStream.php
@@ -0,0 +1,89 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\StreamWrapper\SystemStream.
+ */
+
+namespace Drupal\Core\StreamWrapper;
+
+use \Drupal\Component\Utility\UrlHelper;
+
+/**
+ * Defines a base stream wrapper implementation.
+ *
+ * This class provides a read-only Drupal stream wrapper base class for system
+ * files such as modules, themes and profiles.
+ */
+abstract class SystemStream extends LocalReadOnlyStream {
+
+  /**
+   * Get the module, theme, or profile name of the current URI.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return string
+   *   The extension name.
+   */
+  public function getOwnerName($uri = NULL) {
+    if (!isset($uri)) {
+      $uri = $this->uri;
+    }
+
+    $uri_parts = explode('://', $uri, 2);
+    if (count($uri_parts) === 1) {
+      // The delimiter ('://') was not found in $uri, malformed $uri passed.
+      throw new \InvalidArgumentException('Malformed $uri parameter passed: %s', $uri);
+    }
+    else {
+      list($scheme, $target) = $uri_parts;
+    }
+    // Remove the trailing filename from the path.
+    $length = strpos($target, '/');
+    return ($length === FALSE) ? $target : substr($target, 0, $length);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTarget($uri = NULL) {
+    $target = $this->extractTarget($uri);
+    return file_exists($this->getDirectoryPath($uri) . '/' . $target) ? $target : NULL;
+  }
+
+  /**
+   * Returns the local target of the resource, regardless of whether it exists.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return bool|string
+   *   A path to the local target.
+   */
+  protected function extractTarget($uri = NULL) {
+    // If the owner doesn't exist at all, we don't extract anything.
+    if ($this->getOwnerName($uri) === FALSE) {
+      return FALSE;
+    }
+    $target = parent::getTarget($uri);
+    // Remove the preceding owner name including slash from the path.
+    $start = strpos($target, '/');
+    $target = ($start === FALSE) ? '' : substr($target, $start + 1);
+    return $target;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getExternalUrl($uri = NULL) {
+    $dir = $this->getDirectoryPath($uri);
+    if (empty($dir)) {
+      return FALSE;
+    }
+
+    $target = $this->extractTarget($uri);
+    $path = $target != '' ? '/' . UrlHelper::encodePath(str_replace('\\', '/', $target)) : '';
+    return \Drupal::request()->getUri() . $dir . $path;
+  }
+}
diff --git a/core/lib/Drupal/Core/StreamWrapper/ThemeStream.php b/core/lib/Drupal/Core/StreamWrapper/ThemeStream.php
new file mode 100644
index 0000000..e59efd0
--- /dev/null
+++ b/core/lib/Drupal/Core/StreamWrapper/ThemeStream.php
@@ -0,0 +1,62 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\StreamWrapper\ThemeStream.
+ */
+
+namespace Drupal\Core\StreamWrapper;
+
+/**
+ * Defines a read-only Drupal stream wrapper base class for themes.
+ *
+ * This class extends the complete stream wrapper implementation in LocalStream.
+ * URIs such as "theme://bartik" are expanded to a normal filesystem path
+ * such as "themes/bartik" and then PHP filesystem functions are invoked.
+ *
+ * Specifying "theme://current" returns a stream for the current theme,
+ * "theme://default" returns a stream for the default theme, and "theme://admin"
+ * returns a stream for the admin theme.
+ */
+class ThemeStream extends SystemStream {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getOwnerName($uri = NULL) {
+    $name = parent::getOwnerName($uri);
+    switch ($name) {
+      case 'current':
+        $name = $this->getActiveTheme();
+        break;
+      case 'default':
+        $name =  \Drupal::config('system.theme')->get('default');
+        break;
+      case 'admin':
+        $name =  \Drupal::config('system.theme')->get('admin');
+        break;
+    }
+    // Return name only for enabled themes.
+    return array_key_exists($name, \Drupal::service('theme_handler')->listInfo()) ? $name : FALSE;
+  }
+
+  /**
+   * Gets the theme's directory path.
+   *
+   * @param string $uri
+   *   Optional URI.
+   *
+   * @return string
+   *   String specifying the path.
+   */
+  public function getDirectoryPath($uri = NULL) {
+    return drupal_get_path('theme', $this->getOwnerName($uri));
+  }
+
+  /**
+   * Gets the currently active theme.
+   */
+  protected function getActiveTheme() {
+    return \Drupal::service('theme.negotiator')->determineActiveTheme(\Drupal::service('current_route_match'));
+  }
+}
diff --git a/core/modules/block/tests/modules/block_test/block_test.module b/core/modules/block/tests/modules/block_test/block_test.module
index a527ae1..0583b86 100644
--- a/core/modules/block/tests/modules/block_test/block_test.module
+++ b/core/modules/block/tests/modules/block_test/block_test.module
@@ -8,6 +8,14 @@
 use Drupal\block\BlockPluginInterface;
 
 /**
+ * Implements hook_system_theme_info().
+ */
+function block_test_system_theme_info() {
+  $themes['block_test_theme'] = "module://block_test/themes/block_test_theme/block_test_theme.info.yml";
+  return $themes;
+}
+
+/**
  * Implements hook_block_alter().
  */
 function block_test_block_alter(&$block_info) {
diff --git a/core/modules/breakpoint/tests/breakpoint_theme_test.module b/core/modules/breakpoint/tests/breakpoint_theme_test.module
new file mode 100644
index 0000000..57e8888
--- /dev/null
+++ b/core/modules/breakpoint/tests/breakpoint_theme_test.module
@@ -0,0 +1,13 @@
+<?php
+/**
+ * @file
+ * Test breakpoint functionality for breakpoints provided by themes.
+ */
+
+/**
+ * Implements hook_system_theme_info().
+ */
+function breakpoint_theme_test_system_theme_info() {
+  $themes['breakpoint_test_theme'] = "module://breakpoint_theme_test/themes/breakpoint_test_theme/breakpoint_test_theme.info.yml";
+  return $themes;
+}
diff --git a/core/modules/color/tests/modules/color_test/color_test.module b/core/modules/color/tests/modules/color_test/color_test.module
index 603906e..b89e5e4 100644
--- a/core/modules/color/tests/modules/color_test/color_test.module
+++ b/core/modules/color/tests/modules/color_test/color_test.module
@@ -9,6 +9,6 @@
  * Implements hook_system_theme_info().
  */
 function color_test_system_theme_info() {
-  $themes['color_test_theme'] = drupal_get_path('module', 'color_test') . '/themes/color_test_theme/color_test_theme.info.yml';
+  $themes['color_test_theme'] = 'module://color_test/themes/color_test_theme/color_test_theme.info.yml';
   return $themes;
 }
diff --git a/core/modules/file/tests/file_test/file_test.dummy.inc b/core/modules/file/tests/file_test/file_test.dummy.inc
new file mode 100644
index 0000000..a09fd2e
--- /dev/null
+++ b/core/modules/file/tests/file_test/file_test.dummy.inc
@@ -0,0 +1 @@
+Dummy file used by SystemStreamTest.php.
diff --git a/core/modules/search/src/Tests/SearchSimplifyTest.php b/core/modules/search/src/Tests/SearchSimplifyTest.php
index a850750..0a55965 100644
--- a/core/modules/search/src/Tests/SearchSimplifyTest.php
+++ b/core/modules/search/src/Tests/SearchSimplifyTest.php
@@ -24,7 +24,7 @@ function testSearchSimplifyUnicode() {
     // their own lines).  So the even-numbered lines should simplify to nothing,
     // and the odd-numbered lines we need to split into shorter chunks and
     // verify that simplification doesn't lose any characters.
-    $input = file_get_contents(DRUPAL_ROOT . '/core/modules/search/tests/UnicodeTest.txt');
+    $input = file_get_contents('module://search/tests/UnicodeTest.txt');
     $basestrings = explode(chr(10), $input);
     $strings = array();
     foreach ($basestrings as $key => $string) {
diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index 616d064..f60ab48 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -61,6 +61,7 @@
 
   private $moduleFiles;
   private $themeFiles;
+  private $themeData;
 
   /**
    * The configuration directories for this test run.
@@ -101,6 +102,7 @@ protected function beforePrepareEnvironment() {
     if (!isset($this->moduleFiles)) {
       $this->moduleFiles = \Drupal::state()->get('system.module.files') ?: array();
       $this->themeFiles = \Drupal::state()->get('system.theme.files') ?: array();
+      $this->themeData = \Drupal::state()->get('system.theme.data') ?: array();
     }
   }
 
@@ -170,6 +172,7 @@ protected function setUp() {
 
     $this->container->get('state')->set('system.module.files', $this->moduleFiles);
     $this->container->get('state')->set('system.theme.files', $this->themeFiles);
+    $this->container->get('state')->set('system.theme.data', $this->themeData);
 
     // Create a minimal core.extension configuration object so that the list of
     // enabled modules can be maintained allowing
diff --git a/core/modules/system/src/Tests/File/SystemStreamUnitTest.php b/core/modules/system/src/Tests/File/SystemStreamUnitTest.php
new file mode 100644
index 0000000..062a64b
--- /dev/null
+++ b/core/modules/system/src/Tests/File/SystemStreamUnitTest.php
@@ -0,0 +1,260 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\File\SystemStreamUnitTest.
+ */
+
+namespace Drupal\system\Tests\File;
+
+use Drupal\Core\Site\Settings;
+use Drupal\simpletest\KernelTestBase;
+
+/**
+ * Unit tests for system stream wrapper functions.
+ *
+ * @group system
+ */
+class SystemStreamUnitTest extends KernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system', 'file', 'file_test');
+
+  /**
+   * Original test environment settings.
+   *
+   * @var array
+   */
+  protected $originalSettings;
+
+  /**
+  /**
+   * Original theme files list.
+   *
+   * @var array
+   */
+  protected $originalThemeFiles;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getInfo() {
+    return array(
+      'name' => 'System Stream wrappers',
+      'description' => 'Unit tests system stream wrapper functions.',
+      'group' => 'File API',
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+    drupal_static_reset('file_get_stream_wrappers');
+    // Add default profile for the purposes of this test
+    $this->originalSettings = Settings::getAll();
+    new Settings(array_merge(array('install_profile' => 'standard'), $this->originalSettings));
+
+    // Drupal::container() doesn't contain theme state info which is already
+    // saved in KernelTestBase::container. Need to transfer this across.
+    $this->originalThemeData = \Drupal::state()->get('system.theme.data');
+    \Drupal::state()->set('system.theme.data', $this->container->get('state')->get('system.theme.data'));
+//    $this->originalThemeFiles = \Drupal::state()->get('system.theme.files');
+//    \Drupal::state()->set('system.theme.files', $this->container->get('state')->get('system.theme.files'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function tearDown() {
+    // Restore changes made in setUp().
+    new Settings($this->originalSettings);
+    \Drupal::state()->set('system.theme.data', $this->originalThemeData);
+    \Drupal::state()->set('system.theme.files', $this->originalThemeFiles);
+    parent::tearDown();
+  }
+
+  /**
+   * Test the Module stream wrapper functions.
+   */
+  public function testModuleStream() {
+    // Generate a module stream wrapper instance.
+    $uri1 = 'module://system';
+    $uri2 = 'module://system/css/system.admin.css';
+    $uri3 = 'module://file_test/file_test.dummy.inc';
+    $uri4 = 'module://file_test/includes/file_test.dummy.inc';
+    $uri5 = 'module://ckeditor/ckeditor.info.yml';
+    $uri6 = 'module://foo_bar/foo.bar.js';
+    $instance = file_stream_wrapper_get_instance_by_scheme('module');
+    /* @var $instance \Drupal\Core\StreamWrapper\ModuleStream */
+
+    // getOwnerName()
+    $this->assertEqual($instance->getOwnerName($uri1), 'system', 'Extract module name from a partial URI.');
+    $this->assertEqual($instance->getOwnerName($uri2), 'system', 'Extract module name for a resource located in a subdirectory.');
+    $this->assertEqual($instance->getOwnerName($uri3), 'file_test', 'Extract module name for a module located in a subdirectory.');
+    $this->assertEqual($instance->getOwnerName($uri4), 'file_test', 'Extract module name even for a non-existing resource, as long as the module exists.');
+    $this->assertFalse($instance->getOwnerName($uri5), "Fail returning a disabled module's name.");
+    $this->assertFalse($instance->getOwnerName($uri6), "Fail returning a non-existing module's name.");
+
+    // getTarget()
+    $this->assertEqual($instance->getTarget($uri1), '', 'Return empty target from a partial URI.');
+    $this->assertEqual($instance->getTarget($uri2), 'css/system.admin.css', 'Extract target for a resource located in a subdirectory.');
+    $this->assertEqual($instance->getTarget($uri3), 'file_test.dummy.inc', 'Extract target for a module in a non-standard location.');
+    $this->assertFalse($instance->getTarget($uri4), 'Fail returning a target for a non-existing resource.');
+    $this->assertFalse($instance->getTarget($uri5), "Fail returning a target within a disabled module.");
+    $this->assertFalse($instance->getTarget($uri6), "Fail returning a target within a non-existing module.");
+
+    // getDirectoryPath()
+    $this->assertEqual($instance->getDirectoryPath($uri1), 'core/modules/system', "Lookup module's directory path for a partial URI.");
+    $this->assertEqual($instance->getDirectoryPath($uri2), 'core/modules/system', "Lookup module's directory path for a resource located in a subdirectory.");
+    $this->assertEqual($instance->getDirectoryPath($uri3), 'core/modules/file/tests/file_test', "Lookup module's directory path for a module located in a subdirectory.");
+    $this->assertEqual($instance->getDirectoryPath($uri4), 'core/modules/file/tests/file_test', "Lookup module's directory path even for a non-existing resource, as long as the module exists.");
+    $this->assertFalse($instance->getDirectoryPath($uri5), "Fail returning a disabled module's directory path");
+    $this->assertFalse($instance->getDirectoryPath($uri6), "Fail returning a non-existing module's directory path.");
+
+    // getExternalUrl()
+    $base_url = \Drupal::request()->getUri();
+    $this->assertEqual($instance->getExternalUrl($uri1), $base_url . 'core/modules/system', "Return the external url for the module directory path.");
+    $this->assertEqual($instance->getExternalUrl($uri2), $base_url . 'core/modules/system/css/system.admin.css', "Return the external url of a resource located in a subdirectory.");
+    $this->assertEqual($instance->getExternalUrl($uri3), $base_url . 'core/modules/file/tests/file_test/file_test.dummy.inc', "Return the external url of an include file located in a subdirectory.");
+    $this->assertEqual($instance->getExternalUrl($uri4), $base_url . 'core/modules/file/tests/file_test/includes/file_test.dummy.inc', "Return the external url even for a non-existing resource, as long as the module exists.");
+    $this->assertFalse($instance->getExternalUrl($uri5), "Fail returning the external uri for resources in a disabled module.");
+    $this->assertFalse($instance->getExternalUrl($uri6), "Fail returning the external uri for resources in a non-existing module.");
+  }
+
+  /**
+   * Test the Profile stream wrapper functions.
+   */
+  public function testProfileStream() {
+    $uri1 = 'profile://minimal';
+    $uri2 = 'profile://minimal/config/install/block.block.stark_login.yml';
+    $uri3 = 'profile://minimal/config/install/node.type.article.yml';
+    $uri4 = 'profile://foo_bar/';
+    $uri5 = 'profile://current';
+    $uri6 = 'profile://current/standard.info.yml';
+    $instance = file_stream_wrapper_get_instance_by_scheme('profile');
+    /* @var $instance \Drupal\Core\StreamWrapper\ProfileStream */
+
+    // getOwnerName()
+    $this->assertEqual($instance->getOwnerName($uri1), 'minimal', "Extract profile's name from a partial URI.");
+    $this->assertEqual($instance->getOwnerName($uri2), 'minimal', "Extract profile's name for a resource located in a subdirectory.");
+    $this->assertEqual($instance->getOwnerName($uri3), 'minimal', "Extract profile's name even for a non-existing resource, as long as the profile exists.");
+    $this->assertFalse($instance->getOwnerName($uri4), "Fail returning a non-existing profile's name.");
+    $this->assertEqual($instance->getOwnerName($uri5), 'standard', format_string('Lookup real name of %current for a partial URI.', array('%current' => 'profile://current')));
+    $this->assertEqual($instance->getOwnerName($uri6), 'standard', format_string('Lookup real name of %current for a resource.', array('%current' => 'profile://current')));
+
+    // getTarget()
+    $this->assertEqual($instance->getTarget($uri1), '', 'Return empty target for a partial URI giving only the profile.');
+    $this->assertEqual($instance->getTarget($uri2), 'config/install/block.block.stark_login.yml', 'Extract target for a resource located in a subdirectory.');
+    $this->assertFalse($instance->getTarget($uri3), 'Fail returning a target for a non-existing resource.');
+    $this->assertFalse($instance->getTarget($uri4), 'Fail returning a target within a non-existing profile.');
+    $this->assertEqual($instance->getTarget($uri5), '', format_string('Return empty target for a partial URI giving only %current.', array('%current' => 'profile://current')));
+    $this->assertEqual($instance->getTarget($uri6), 'standard.info.yml', format_string("Extract target from a resource within %current.", array('%current' => 'profile://current')));
+
+    // getDirectoryPath()
+    $this->assertEqual($instance->getDirectoryPath($uri1), 'core/profiles/minimal', "Lookup profile's directory path for a partial URI.");
+    $this->assertEqual($instance->getDirectoryPath($uri2), 'core/profiles/minimal', "Lookup profile's directory path for a resource located in a subdirectory.");
+    $this->assertEqual($instance->getDirectoryPath($uri3), 'core/profiles/minimal', "Lookup profile's directory path even for a non-existing resource, as long as the profile exists.");
+    $this->assertFalse($instance->getDirectoryPath($uri4), "Fail returning a non-existing profile's directory path.");
+    $this->assertEqual($instance->getDirectoryPath($uri5), 'core/profiles/standard', format_string('Lookup real directory path of %current for a partial URI.', array('%current' => 'profile://current')));
+    $this->assertEqual($instance->getDirectoryPath($uri6), 'core/profiles/standard', format_string('Lookup real directory path of %current for a resource.', array('%current' => 'profile://current')));
+
+    // getExternalUrl()
+    $base_url = \Drupal::request()->getUri();
+    $this->assertEqual($instance->getExternalUrl($uri1), $base_url . 'core/profiles/minimal', "Return the external url for the profile directory path.");
+    $this->assertEqual($instance->getExternalUrl($uri2), $base_url . 'core/profiles/minimal/config/install/block.block.stark_login.yml', "Return the external url of a file located in a subdirectory.");
+    $this->assertEqual($instance->getExternalUrl($uri3), $base_url . 'core/profiles/minimal/config/install/node.type.article.yml', "Return the external url of a non-existing file located in a subdirectory.");
+    $this->assertFalse($instance->getExternalUrl($uri4), "Fail returning the external uri for a disabled profile.");
+    $this->assertEqual($instance->getExternalUrl($uri5), $base_url . 'core/profiles/standard', format_string('Lookup the external url of %current for a partial URI.', array('%current' => 'profile://current')));
+    $this->assertEqual($instance->getExternalUrl($uri6), $base_url . 'core/profiles/standard/standard.info.yml', format_string('Lookup the external url of %current for a resource.', array('%current' => 'profile://current')));
+  }
+
+  /**
+   * Test the Theme stream wrapper functions.
+   */
+  public function testThemeStream() {
+    // Disable Bartik theme.
+    $system_theme_disabled = \Drupal::config('system.theme.disabled');
+    $this->assertNotIdentical($system_theme_disabled->get('bartik'), 0, format_string('%bartik theme was enabled.', array('%bartik' => 'Bartik')));
+    $system_theme_disabled->set('bartik', 0)->save();
+    $this->assertIdentical($system_theme_disabled->get('bartik'), 0, format_string('Now disable %bartik theme.', array('%bartik' => 'Bartik')));
+
+    // Set admin theme to Seven.
+    $system_theme = \Drupal::config('system.theme');
+    $this->assertNull($system_theme->get('admin'), 'No admin theme was set.');
+    $system_theme->set('admin', 'seven')->save();
+    $this->assertEqual($system_theme->get('admin'), 'seven', format_string('Now make %seven the admin theme.', array('%seven' => 'Seven')));
+
+    // Set default theme to Bartik.
+    $system_theme->set('default', 'bartik')->save();
+    $this->assertEqual($system_theme->get('default'), 'bartik', format_string('Now make %bartik the default theme.', array('%bartik' => 'Bartik')));
+
+    $uri1 = 'theme://seven';
+    $uri2 = 'theme://seven/style.css';
+    $uri3 = 'theme://bartik/color/preview.js';
+    $uri4 = 'theme://fifteen/screenshot.png';
+    $uri5 = 'theme://current';
+    $uri6 = 'theme://current/logo.png';
+    $uri7 = 'theme://default';
+    $uri8 = 'theme://default/bartik.info.yml';
+    $uri9 = 'theme://admin';
+    $uri10 = 'theme://admin/fake.info.yml';
+    $instance = file_stream_wrapper_get_instance_by_scheme('theme');
+    /* @var $instance \Drupal\Core\StreamWrapper\ThemeStream */
+
+    // getOwnerName()
+    $this->assertEqual($instance->getOwnerName($uri1), 'seven', "Extract theme's name from a partial URI.");
+    $this->assertEqual($instance->getOwnerName($uri2), 'seven', "Extract theme's name from a full URI.");
+    $this->assertEqual($instance->getOwnerName($uri3), 'bartik', "Extract theme's name from a full URI with subdirectory.");
+    $this->assertFalse($instance->getOwnerName($uri4), "Fail returning a non-existing theme's name.");
+    $this->assertEqual($instance->getOwnerName($uri5), 'bartik', format_string('Lookup real name of %current for a partial URI.', array('%current' => 'theme://current')) . $instance->getOwnerName($uri5));
+    $this->assertEqual($instance->getOwnerName($uri6), 'bartik', format_string('Lookup real name of %current for a resource.', array('%current' => 'theme://current')) . $instance->getOwnerName($uri6));
+    $this->assertEqual($instance->getOwnerName($uri7), 'bartik', format_string('Lookup real name of %default for a partial URI.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getOwnerName($uri8), 'bartik', format_string('Lookup real name of %default for a resource.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getOwnerName($uri9), 'seven', format_string('Lookup real name of %admin for a partial URI.', array('%admin' => 'theme://admin')));
+    $this->assertEqual($instance->getOwnerName($uri10), 'seven', format_string('Lookup real name of %admin even for a non-existing resource.', array('%admin' => 'theme://admin')));
+
+    // getTarget()
+    $this->assertEqual($instance->getTarget($uri1), '', 'Return empty target for a partial URI giving only the theme.');
+    $this->assertFalse($instance->getTarget($uri2), 'Fail returning a target for a non-existent resource.');
+    $this->assertEqual($instance->getTarget($uri3), 'color/preview.js', 'Extract target for a resource located in a subdirectory.');
+    $this->assertFalse($instance->getTarget($uri4), 'Fail returning a target within a non-existing theme.');
+    $this->assertEqual($instance->getTarget($uri5), '', format_string('Return empty target for a partial URI giving only %current.', array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getTarget($uri6), 'logo.png', format_string("Extract target from a resource within %current.", array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getTarget($uri7), '', format_string('Return empty target for a partial URI giving only %default.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getTarget($uri8), 'bartik.info.yml', format_string("Extract target from a resource located in a subdirectory of %default.", array('%default' => 'theme://default')) . $instance->getTarget($uri8));
+    $this->assertEqual($instance->getTarget($uri9), '', format_string('Return empty target for a partial URI giving only %admin.', array('%admin' => 'theme://admin')));
+    $this->assertFalse($instance->getTarget($uri10), format_string("Fail returning target for a non-existing resource within %admin.", array('%admin' => 'theme://admin')));
+
+    // getDirectoryPath()
+    $this->assertEqual($instance->getDirectoryPath($uri1), 'core/themes/seven', "Lookup theme's directory path for a partial URI.");
+    $this->assertEqual($instance->getDirectoryPath($uri2), 'core/themes/seven', "Lookup theme's directory path for a resource located in a subdirectory.");
+    $this->assertEqual($instance->getDirectoryPath($uri3), 'core/themes/bartik', "Lookup theme's directory path for a resource.");
+    $this->assertFalse($instance->getDirectoryPath($uri4), "Fail returning a non-existing theme's directory path.");
+    $this->assertEqual($instance->getDirectoryPath($uri5), 'core/themes/bartik', format_string('Lookup real directory path of %current for a partial URI.', array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getDirectoryPath($uri6), 'core/themes/bartik', format_string('Lookup real directory path of %current for a resource.', array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getDirectoryPath($uri7), 'core/themes/bartik', format_string('Lookup real directory path of %default for a partial URI.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getDirectoryPath($uri8), 'core/themes/bartik', format_string('Lookup real directory path of %default for a resource.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getDirectoryPath($uri9), 'core/themes/seven', format_string('Lookup real directory path of %admin for a partial URI.', array('%admin' => 'theme://admin')));
+    $this->assertEqual($instance->getDirectoryPath($uri10), 'core/themes/seven', format_string('Lookup real directory path of %admin for a resource.', array('%admin' => 'theme://admin')));
+
+    // getExternalUrl()
+    $base_url = \Drupal::request()->getUri();
+    $this->assertEqual($instance->getExternalUrl($uri1), $base_url . 'core/themes/seven', "Lookup theme's external url for a partial URI.");
+    $this->assertEqual($instance->getExternalUrl($uri2), $base_url . 'core/themes/seven/style.css', "Lookup theme's external url for a resource located in a subdirectory.");
+    $this->assertEqual($instance->getExternalUrl($uri3), $base_url . 'core/themes/bartik/color/preview.js', "Lookup theme's external url for a resource.");
+    $this->assertFalse($instance->getExternalUrl($uri4), "Fail returning a non-existing theme's external url.");
+    $this->assertEqual($instance->getExternalUrl($uri5), $base_url . 'core/themes/bartik', format_string('Lookup real external url of %current for a partial URI.', array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getExternalUrl($uri6), $base_url . 'core/themes/bartik/logo.png', format_string('Lookup external url of %current for a resource.', array('%current' => 'theme://current')));
+    $this->assertEqual($instance->getExternalUrl($uri7), $base_url . 'core/themes/bartik', format_string('Lookup external url of %default for a partial URI.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getExternalUrl($uri8), $base_url . 'core/themes/bartik/bartik.info.yml', format_string('Lookup external url of %default for a resource.', array('%default' => 'theme://default')));
+    $this->assertEqual($instance->getExternalUrl($uri9), $base_url . 'core/themes/seven', format_string('Lookup external url of %admin for a partial URI.', array('%admin' => 'theme://admin')));
+    $this->assertEqual($instance->getExternalUrl($uri10), $base_url . 'core/themes/seven/fake.info.yml', format_string('Lookup external url of %admin for a resource.', array('%admin' => 'theme://admin')));
+
+  }
+}
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 117dc49..3829dab 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -735,6 +735,24 @@ function system_stream_wrappers() {
       'description' => new TranslationWrapper('Temporary local files for upload and previews.'),
       'type' => STREAM_WRAPPERS_LOCAL_HIDDEN,
     ),
+    'module' => array(
+      'name' => t('Module files'),
+      'class' => 'Drupal\Core\StreamWrapper\ModuleStream',
+      'description' => t('Local module files.'),
+      'type' => STREAM_WRAPPERS_READ,
+    ),
+    'theme' => array(
+      'name' => t('Theme files'),
+      'class' => 'Drupal\Core\StreamWrapper\ThemeStream',
+      'description' => t('Local theme files.'),
+      'type' => STREAM_WRAPPERS_READ,
+    ),
+    'profile' => array(
+      'name' => t('Profile files'),
+      'class' => 'Drupal\Core\StreamWrapper\ProfileStream',
+      'description' => t('Local profile files.'),
+      'type' => STREAM_WRAPPERS_READ,
+    ),
   );
 
   // Only register the private file stream wrapper if a file path has been set.
diff --git a/core/modules/system/tests/modules/ajax_test/ajax_test.module b/core/modules/system/tests/modules/ajax_test/ajax_test.module
index eee24f3..e427ca7 100644
--- a/core/modules/system/tests/modules/ajax_test/ajax_test.module
+++ b/core/modules/system/tests/modules/ajax_test/ajax_test.module
@@ -13,6 +13,14 @@
 use Drupal\Core\Ajax\HtmlCommand;
 
 /**
+ * Implements hook_system_theme_info().
+ */
+function ajax_test_system_theme_info() {
+  $themes['test_theme'] = "module://system/tests/themes/test_theme/test_theme.info.yml";
+  return $themes;
+}
+
+/**
  * Menu callback: Returns an element suitable for use by
  * \Drupal\Core\Ajax\AjaxResponse::ajaxRender().
  *
diff --git a/core/modules/system/tests/modules/theme_test/theme_test.module b/core/modules/system/tests/modules/theme_test/theme_test.module
index b6f13c8..b8d3c2a 100644
--- a/core/modules/system/tests/modules/theme_test/theme_test.module
+++ b/core/modules/system/tests/modules/theme_test/theme_test.module
@@ -49,13 +49,21 @@ function theme_test_theme($existing, $type, $theme, $path) {
   $items['theme_test_function_template_override'] = array(
     'variables' => array(),
   );
-  $info['test_theme_not_existing_function'] = array(
-    'function' => 'test_theme_not_existing_function',
-  );
   return $items;
 }
 
 /**
+ * Implements hook_system_theme_info().
+ */
+function theme_test_system_theme_info() {
+  $themes['test_theme'] = "module://system/tests/themes/test_theme/test_theme.info.yml";
+  $themes['test_basetheme'] = "module://system/tests/themes/test_basetheme/test_basetheme.info.yml";
+  $themes['test_subtheme'] = "module://system/tests/themes/test_subtheme/test_subtheme.info.yml";
+  $themes['test_theme_phptemplate'] = "module://system/tests/themes/test_theme_phptemplate/test_theme_phptemplate.info.yml";
+  return $themes;
+}
+
+/**
  * Implements hook_preprocess_HOOK() for HTML document templates.
  */
 function theme_test_preprocess_html(&$variables) {
diff --git a/core/modules/update/tests/modules/update_test/update_test.module b/core/modules/update/tests/modules/update_test/update_test.module
index 536d330..b99bf9e 100644
--- a/core/modules/update/tests/modules/update_test/update_test.module
+++ b/core/modules/update/tests/modules/update_test/update_test.module
@@ -10,6 +10,15 @@
  */
 
 /**
+ * Implements hook_system_theme_info().
+ */
+function update_test_system_theme_info() {
+  $themes['update_test_basetheme'] = "module://update/tests/themes/update_test_basetheme/update_test_basetheme.info.yml";
+  $themes['update_test_subtheme'] = "module://update/tests/themes/update_test_subtheme/update_test_subtheme.info.yml";
+  return $themes;
+}
+
+/**
  * Implements hook_system_info_alter().
  *
  * Checks the 'update_test.settings:system_info' configuration and sees if we