6 files declare their use of ErrorHandler in Zircon Profile 8

DebugClassLoaderTest.php in vendor/symfony/debug/Tests/DebugClassLoaderTest.php

DebugHandlersListener.php in vendor/symfony/http-kernel/EventListener/DebugHandlersListener.php

DebugHandlersListenerTest.php in vendor/symfony/http-kernel/Tests/EventListener/DebugHandlersListenerTest.php

ErrorHandler.php in vendor/symfony/http-kernel/Debug/ErrorHandler.php

ErrorHandlerTest.php in vendor/symfony/debug/Tests/ErrorHandlerTest.php

ErrorsLoggerListener.php in vendor/symfony/http-kernel/EventListener/ErrorsLoggerListener.php