diff --git a/core/includes/assets.inc b/core/includes/assets.inc
new file mode 100644
index 0000000..b11866e
--- /dev/null
+++ b/core/includes/assets.inc
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * @file
+ * Functions and interfaces for asset handling.
+ */
+
+use Drupal\Core\Assets\AssetCollectionFactory;
+
+/**
+ * Instantiates and statically caches the correct classes for asset types.
+ *
+ * Classes implementing Drupal\Core\Asset\AssetInterface can register
+ * themselves for specific types.
+ *
+ * @param $type
+ *   The asset type for which the asset object should be returned.
+ *
+ * @return Drupal\Core\Cache\AssetInterface
+ *   The asset object associated with the specified type.
+ *
+ * @see Drupal\Core\Cache\AssetInterface
+ */
+function assets($type) {
+  // Use the advanced drupal_static() pattern, since this is called very often.
+  static $drupal_static_fast;
+  if (!isset($drupal_static_fast)) {
+    $drupal_static_fast['assets'] = &drupal_static(__FUNCTION__, array());
+  }
+  $assets = &$drupal_static_fast['assets'];
+
+  if (!isset($assets[$type])) {
+    $assets[$type] = AssetCollectionFactory::get($type);
+  }
+  return $assets[$type];
+}
\ No newline at end of file
diff --git a/core/includes/common.inc b/core/includes/common.inc
index aea8529..baeb6b6 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -2687,43 +2687,18 @@ function drupal_add_css($data = NULL, $options = NULL) {
  *
  * @see drupal_add_css()
  */
-function drupal_get_css($css = NULL, $skip_alter = FALSE) {
-  if (!isset($css)) {
-    $css = drupal_add_css();
-  }
+function drupal_get_css($css = NULL, $skip_alter = FALSE, $group = NULL) {
+  $styles = assets('css');
+  $styles->set($css, $group);
 
   // Allow modules and themes to alter the CSS items.
   if (!$skip_alter) {
-    drupal_alter('css', $css);
-  }
-
-  // Sort CSS items, so that they appear in the correct order.
-  uasort($css, 'drupal_sort_css_js');
-
-  // Remove the overridden CSS files. Later CSS files override former ones.
-  $previous_item = array();
-  foreach ($css as $key => $item) {
-    if ($item['type'] == 'file') {
-      // If defined, force a unique basename for this file.
-      $basename = isset($item['basename']) ? $item['basename'] : drupal_basename($item['data']);
-      if (isset($previous_item[$basename])) {
-        // Remove the previous item that shared the same base name.
-        unset($css[$previous_item[$basename]]);
-      }
-      $previous_item[$basename] = $key;
-    }
+    drupal_alter('css', $styles->assets);
   }
 
-  // Render the HTML needed to load the CSS.
-  $styles = array(
-    '#type' => 'styles',
-    '#items' => $css,
-  );
-  if (!empty($setting)) {
-    $styles['#attached']['js'][] = array('type' => 'setting', 'data' => $setting);
-  }
+  $styles->sort();
 
-  return drupal_render($styles);
+  return $styles->render();
 }
 
 /**
@@ -4876,6 +4851,7 @@ function _drupal_bootstrap_code() {
   require_once DRUPAL_ROOT . '/core/includes/errors.inc';
   require_once DRUPAL_ROOT . '/core/includes/schema.inc';
   require_once DRUPAL_ROOT . '/core/includes/entity.inc';
+  require_once DRUPAL_ROOT . '/core/includes/assets.inc';
 
   // Load all enabled modules
   module_load_all();
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 17e2a66..37af94b 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -285,6 +285,7 @@ function install_begin_request(&$install_state) {
   include_once DRUPAL_ROOT . '/core/includes/module.inc';
   include_once DRUPAL_ROOT . '/core/includes/session.inc';
   require_once DRUPAL_ROOT . '/core/includes/entity.inc';
+  require_once DRUPAL_ROOT . '/core/includes/assets.inc';
 
   // Determine whether the configuration system is ready to operate.
   $install_state['config_verified'] = install_verify_config_directory(CONFIG_ACTIVE_DIRECTORY) && install_verify_config_directory(CONFIG_STAGING_DIRECTORY);
diff --git a/core/lib/Drupal/Core/Assets/AssetCollectionFactory.php b/core/lib/Drupal/Core/Assets/AssetCollectionFactory.php
new file mode 100644
index 0000000..43a35f7
--- /dev/null
+++ b/core/lib/Drupal/Core/Assets/AssetCollectionFactory.php
@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Assets\AssetFactory.
+ */
+
+namespace Drupal\Core\Assets;
+
+/**
+ * Defines the asset factory.
+ */
+class AssetCollectionFactory {
+
+  /**
+   * Instantiates an asset class for a given asset type.
+   *
+   * Classes implementing Drupal\Core\Assets\AssetInterface can register
+   * themselves for specific types.
+   *
+   * @param string $type
+   *   The type for which an asset object should be returned.
+   *
+   * @return Drupal\Core\Assets\AssetInterface
+   *   The asset object associated with the specified type.
+   */
+  public static function get($type) {
+    // Check whether there is a custom class defined for the requested type or
+    // use the default 'type' definition otherwise.
+    $asset_types = self::getTypes();
+    $class = $asset_types[$type];
+    return new $class($type);
+  }
+
+  /**
+   * Returns a list of asset types for this site.
+   *
+   * @return array
+   *   An associative array with types as keys, and asset class names as
+   *   value.
+   */
+  public static function getTypes() {
+    // @todo Just copying CacheFactory here, but really should use config.
+    // See _aggregator_get_variables().
+    // Perhaps store in system module config.
+    // Need to return other config, too, bundler and packager variables for each type. 
+    global $conf;
+    $asset_types = isset($conf['asset_classes']) ? $conf['asset_classes'] : array();
+    // Ensure there is a default 'generic' definition.
+    $asset_types += array('css' => 'Drupal\Core\Assets\CssAssetCollection');
+    $asset_types += array('js' => 'Drupal\Core\Assets\JsAssetCollection');
+    return $asset_types;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Assets/AssetCollectionInterface.php b/core/lib/Drupal/Core/Assets/AssetCollectionInterface.php
new file mode 100644
index 0000000..b578380
--- /dev/null
+++ b/core/lib/Drupal/Core/Assets/AssetCollectionInterface.php
@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\Assets\AssetInterface.
+ */
+
+namespace Drupal\Core\Assets;
+
+/**
+ * Defines an interface for asset collections.
+ *
+ * @see assets()
+ */
+interface AssetCollectionInterface {
+
+  /**
+   * Returns array of assets.
+   *
+   * @param $group
+   *   The group of assets to return.
+   *
+   * @return
+   *   Array of assets as returned by drupal_add_css() or drupal_add_js().
+   */
+  function get($group = NULL);
+
+  /**
+   * Defines the current assets.
+   *
+   * @param array $data
+   *   Array of assets as returned by drupal_add_css() or drupal_add_js()..
+   */
+  function set($data, $group = NULL);
+
+  /**
+   * Sorts the assets.
+   */
+  function sort();
+
+  /**
+   * Renders the assets into the appropriate HTML.
+   *
+   * @return
+   *   HTML string.
+   */
+  function render();
+}
diff --git a/core/lib/Drupal/Core/Assets/CssAssetCollection.php b/core/lib/Drupal/Core/Assets/CssAssetCollection.php
new file mode 100644
index 0000000..41b63b0
--- /dev/null
+++ b/core/lib/Drupal/Core/Assets/CssAssetCollection.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\Assets\CssAssetCollection.
+ */
+
+namespace Drupal\Core\Assets;
+
+/**
+ * Defines a default Asset implementation.
+ *
+ * This is Drupal's default CSS Asset implementation.
+ */
+class CssAssetCollection implements AssetCollectionInterface {
+
+  public $assets = array();
+
+  /**
+   * Implements Drupal\Core\Assets\AssetCollectionInterface::get().
+   */
+  function get($group = NULL) {
+    $assets = array();
+    if ($group === NULL) {
+      $assets = $this->assets;
+    }
+    foreach ($this->assets as $file) {
+      if (isset($file['group']) && $file['group'] == $group) {
+        $assets[] = $file;
+      }
+    }
+    return $assets;
+  }
+
+  /**
+   * Implements Drupal\Core\Assets\AssetCollectionInterface::set().
+   */
+  function set($css = array(), $group = NULL) {
+    if (empty($css)) {
+      $this->assets = drupal_add_css();
+      if (!empty($group) || $group === 0) {
+        $this->assets = $this->get($group);
+      }
+    }
+    else {
+      $this->assets = $css;
+    }
+  }
+
+  /**
+   * Implements Drupal\Core\Assets\AssetCollectionInterface::set().
+   */
+  function sort() {
+    // Sort CSS items, so that they appear in the correct order.
+    uasort($this->assets, 'drupal_sort_css_js');
+
+    // Remove the overridden CSS files. Later CSS files override former ones.
+    $previous_item = array();
+    foreach ($this->assets as $key => $item) {
+      if ($item['type'] == 'file') {
+        // If defined, force a unique basename for this file.
+        $basename = isset($item['basename']) ? $item['basename'] : drupal_basename($item['data']);
+        if (isset($previous_item[$basename])) {
+          // Remove the previous item that shared the same base name.
+          unset($this->assets[$previous_item[$basename]]);
+        }
+        $previous_item[$basename] = $key;
+      }
+    }
+  }
+
+  /**
+   * Implements Drupal\Core\Assets\AssetCollectionInterface::set().
+   */
+  function render() {
+    // Render the HTML needed to load the CSS.
+    $styles = array(
+      '#type' => 'styles',
+      '#items' => $this->assets,
+    );
+    return drupal_render($styles);
+  }
+
+}