diff --git a/core/lib/Drupal/Core/Config/ConfigImporter.php b/core/lib/Drupal/Core/Config/ConfigImporter.php
index 715138f..3f7db46 100644
--- a/core/lib/Drupal/Core/Config/ConfigImporter.php
+++ b/core/lib/Drupal/Core/Config/ConfigImporter.php
@@ -786,8 +786,7 @@ protected function processExtension($type, $op, $name) {
 
     $this->setProcessedExtension($type, $op, $name);
     \Drupal::service('config.installer')
-      ->setSyncing(FALSE)
-      ->resetSourceStorage();
+      ->setSyncing(FALSE);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
index 96c042b..b5aeb7f 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -10,8 +10,6 @@
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Config\Entity\ConfigDependencyManager;
 use Drupal\Core\Entity\EntityTypeInterface;
-use Drupal\Core\Site\Settings;
-use Psr\Log\LoggerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 class ConfigInstaller implements ConfigInstallerInterface {
@@ -321,10 +319,17 @@ public function setSourceStorage(StorageInterface $storage) {
   }
 
   /**
-   * {@inheritdoc}
+   * Resets the configuration storage that provides the default configuration.
+   *
+   * @return $this
    */
-  public function resetSourceStorage() {
-    $this->sourceStorage = null;
+  protected function resetSourceStorage() {
+    // Do not reset the source storage when synchronizing configuration, since
+    // that would needlessly trigger a reload of the whole configuration to
+    // be imported.
+    if (!$this->isSyncing()) {
+      $this->sourceStorage = NULL;
+    }
     return $this;
   }
 
@@ -335,18 +340,12 @@ public function resetSourceStorage() {
    *   (optional) The configuration collection. Defaults to the default
    *   collection.
    *
-   * @return \Drupal\Core\Config\StorageInterface
+   * @return \Drupal\Core\Config\StorageInterface|null
    *   The configuration storage that provides the default configuration.
+   *   Returns null if the source storage has not been set.
    */
   public function getSourceStorage($collection = StorageInterface::DEFAULT_COLLECTION) {
-    if (!isset($this->sourceStorage)) {
-      throw new ConfigException('This should not happen');
-      // Default to using the ExtensionInstallStorage which searches extension's
-      // config directories for default configuration. Only include the profile
-      // configuration during Drupal installation.
-      // $this->sourceStorage = new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_INSTALL_DIRECTORY, $collection, drupal_installation_attempted());
-    }
-    if ($this->sourceStorage->getCollectionName() != $collection) {
+    if (isset($this->sourceStorage) && $this->sourceStorage->getCollectionName() != $collection) {
       $this->sourceStorage = $this->sourceStorage->createCollection($collection);
     }
     return $this->sourceStorage;
@@ -446,7 +445,7 @@ public function checkConfigurationToInstall($type, $name) {
     // has the same name as a module's configuration will be used instead.
     if ($name != $this->drupalGetProfile()) {
       // Throw an exception if the module being installed contains configuration
-      // that already exits. Additionally, can not continue installing more
+      // that already exists. Additionally, can not continue installing more
       // modules because those may depend on the current module being installed.
       $existing_configuration = $this->findPreExistingConfiguration();
       if (!empty($existing_configuration)) {
@@ -587,9 +586,9 @@ protected function drupalGetPath($type, $name) {
    * Wrapper for drupal_get_profile().
    *
    * @return string|null $profile
-   *   The name of the installation profile or NULL if no installation profile is
-   *   currently active. This is the case for example during the first steps of
-   *   the installer or during unit tests.
+   *   The name of the installation profile or NULL if no installation profile
+   *   is currently active. This is the case for example during the first steps
+   *   of the installer or during unit tests.
    */
   protected function drupalGetProfile() {
     return drupal_get_profile();
diff --git a/core/lib/Drupal/Core/Config/ConfigInstallerInterface.php b/core/lib/Drupal/Core/Config/ConfigInstallerInterface.php
index e49dfe7..bd2dad7 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstallerInterface.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstallerInterface.php
@@ -70,13 +70,6 @@ public function installCollectionDefaultConfig($collection);
   public function setSourceStorage(StorageInterface $storage);
 
   /**
-   * Resets the configuration storage that provides the default configuration.
-   *
-   * @return $this
-   */
-  public function resetSourceStorage();
-
-  /**
    * Sets the status of the isSyncing flag.
    *
    * @param bool $status
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index af2ab64..378dc3c 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -242,12 +242,6 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
             ->setSyncing(TRUE)
             ->setSourceStorage($source_storage);
         }
-        else {
-          // If we're not in a config synchronization reset the source storage
-          // so that the extension install storage will pick up the new
-          // configuration.
-          $config_installer->resetSourceStorage();
-        }
         \Drupal::service('config.installer')->installDefaultConfig('module', $module);
 
         // If the module has no current updates, but has some that were
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index 79ca84c..a493550 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -285,16 +285,6 @@ public function install(array $theme_list, $install_dependencies = TRUE) {
       // Only install default configuration if this theme has not been installed
       // already.
       if (!isset($installed_themes[$key])) {
-        // The default config installation storage only knows about the
-        // currently installed list of themes, so it has to be reset in order to
-        // pick up the default config of the newly installed theme. However, do
-        // not reset the source storage when synchronizing configuration, since
-        // that would needlessly trigger a reload of the whole configuration to
-        // be imported.
-        if (!$this->configInstaller->isSyncing()) {
-          $this->configInstaller->resetSourceStorage();
-        }
-
         // Install default configuration of the theme.
         $this->configInstaller->installDefaultConfig('theme', $key);
       }
diff --git a/core/modules/config/src/Tests/ConfigImportRecreateTest.php b/core/modules/config/src/Tests/ConfigImportRecreateTest.php
index 1c0166d..a8a18bc 100644
--- a/core/modules/config/src/Tests/ConfigImportRecreateTest.php
+++ b/core/modules/config/src/Tests/ConfigImportRecreateTest.php
@@ -93,8 +93,8 @@ public function testRecreateEntity() {
     // will be recreated.
     $creates = $this->configImporter->getUnprocessedConfiguration('create');
     $deletes = $this->configImporter->getUnprocessedConfiguration('delete');
-    $this->assertEqual(5, count($creates), 'There are 4 configuration items to create.');
-    $this->assertEqual(5, count($deletes), 'There are 4 configuration items to delete.');
+    $this->assertEqual(5, count($creates), 'There are 5 configuration items to create.');
+    $this->assertEqual(5, count($deletes), 'There are 5 configuration items to delete.');
     $this->assertEqual(0, count($this->configImporter->getUnprocessedConfiguration('update')), 'There are no configuration items to update.');
     $this->assertIdentical($creates, array_reverse($deletes), 'Deletes and creates contain the same configuration names in opposite orders due to dependencies.');
 
diff --git a/core/modules/views/src/Tests/ViewExecutableTest.php b/core/modules/views/src/Tests/ViewExecutableTest.php
index 6affac2..07ece1b 100644
--- a/core/modules/views/src/Tests/ViewExecutableTest.php
+++ b/core/modules/views/src/Tests/ViewExecutableTest.php
@@ -85,7 +85,8 @@ protected function setUpFixtures() {
     $this->installEntitySchema('comment');
     $this->installSchema('comment', array('comment_entity_statistics'));
     $this->installConfig(array('system', 'field', 'node', 'comment'));
-    // Clear the views data cache so it updated with the new entity information.
+    // Clear the views data cache so it's updated with the new entity
+    // information.
     \Drupal::service('views.views_data')->clear();
 
     entity_create('node_type', array(