"System Icons" refers to icons used for dialogs, popovers, and in settings. This doesn't include "core icons", which are used in the Chrome toolbar.

Some vector icons already exist in the codebase at the incorrect sizes and need to be updated. Examples of places where this is known to occur:

- PageInfoBubbleView / PageInfoUI::GetPermissionIcon
- PermissionPromptImpl
- DownloadItemNotification::SetNotificationIcon

In these cases, the existing icon should be replaced with the same vector icon with less padding around the outside (to compensate for the decreased size), then the size updated to 16dp or 20dp (depending on which size is closer).

When adding new icons please:
 - Check if the icon is available on go/icons and scale it down to 20dp and 16dp.
 - Follow the keyline shapes guidelines.
 - Match the pixel grid as well as possible.
 - Use the same names used on go/icons (example: ic_location_black_16dp).

For further information, please see https://docs.google.com/document/d/1Y89nIBPRtL5sC6engeMp8AZ8gWnnTIuXKXjpNxszWtU/edit?usp=sharing (internal accounts only).