16 files declare their use of Container

bootstrap.inc in drupal/core/includes/bootstrap.inc
Functions that need to be loaded on every Drupal request.
Bundle.php in drupal/core/vendor/symfony/http-kernel/Symfony/Component/HttpKernel/Bundle/Bundle.php
common.inc in drupal/core/includes/common.inc
Common functions that many Drupal modules will need to reference.
ContainerAwareEventDispatcherTest.php in drupal/core/vendor/symfony/event-dispatcher/Symfony/Component/EventDispatcher/Tests/ContainerAwareEventDispatcherTest.php
ContainerBuilder.php in drupal/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
Definition of Drupal\Core\DependencyInjection\Container.
ContainerTest.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/ContainerTest.php
ControllerResolverTest.php in drupal/core/modules/system/lib/Drupal/system/Tests/Routing/ControllerResolverTest.php
Definition of Drupal\system\Tests\Routing\ControllerResolverTest.
Extension.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Extension/Extension.php
PhpDumper.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
RoleAccessCheckTest.php in drupal/core/tests/Drupal/Tests/Core/Route/RoleAccessCheckTest.php
Contains \Drupal\Tests\Core\Route\RoleAccessCheckTest.
services1.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services1.php
services10.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services10.php
services8.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services8.php
services9.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9.php
services9_compiled.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9_compiled.php
ViewUIObjectTest.php in drupal/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewUIObjectTest.php
Contains \Drupal\views_ui\Tests\ViewUIObjectTest.