This directory contains components that are used by ash-chrome only. For C++ code, think of //chromeos/ash/components like top-level //components. Specifically, each component should have its own DEPS to be isolated from other components.
For example, //chromeos/ash/components/account_manager manages the user's GAIA accounts, but only on behalf of ChromeOS code. //components/account_manager_core contains cross-platform support for accounts.
Some subdirectories contain low-level utility code. For example, //chromeos/ash/components/disks has utilities for mounting and unmounting disk volumes.
Much of this code used to live in //chromeos/components. The now sunsetted Lacros project was extracting browser functionality into a separate binary. As part of this migration, code used only by the ash-chrome binary moved into “ash” directories. See the Chrome OS source directory migration design doc for details.