//components/safe_browsing is a layered component (https://sites.google.com/a/chromium.org/dev/developers/design-documents/layered-components-design) to enable it to be shared cleanly on iOS.
The component has the following structure:
A note for //content-based embedders of this component:
//content-based embedders should use the SafeBrowsingBlockingPage, SafeBrowsingUIManager, and SafeBrowsingNavigationThrottle classes. BaseBlockingPage and BaseUIManager exist for Android WebView and should not be used further (crbug.com/1234027).