//content/public is the API exposed to embedders of the content module.
In general, we follow the design of the Blink Public API. This makes it easier for people who're already familiar with it, and also keeps things consistent.
//content/publicshould contain only interfaces, enums, structs and (rarely) static functions.
//content/public/test. We allow concrete classes that chrome test classes derive from or use in here.
//content/publicshould be inside implementation directories, e.g.
//content/public, we do allow
.mojomfiles (see discussion). If a mojom is only used inside content, it should be in
//content/common. If it’s an interface that is implemented or called by content's embedder, then it belongs in
//contentshould be in the
RenderViewObserver) this might cover things like automatic registration/unregistration. Normally we would put this small code in headers, but because of the clang checks against putting code in headers, we’re forced to put it in .cc files (we don't want to make a clang exception for the
content/publicdirectory since that would lead to confusion).
//content/publicbut instead some module that's higher level.
constidentifier can be added to simple getter APIs implemented by content. Don‘t add
constto interfaces implemented by the embedder, where we can’t make assumptions about what the embedder needs to implement it.
RenderViewObserver) should only have void methods. This is because otherwise the order that observers are registered would matter, and we don‘t want that. The only exception is
OnMessageReceived(), which is fine since only one observer class handles each particular IPC, so ordering doesn’t make a difference.