1 KeyedService is a layered component
2 (https://sites.google.com/a/chromium.org/dev/developers/design-documents/layered-components-design)
3 to enable it to be shared cleanly on iOS.
5 This component has the following structure:
7 - core/: shared code that does not depend on src/content/ or src/ios/
8 - content/: Code based on the content layer.
9 - ios/: Code based on src/ios.