This directory provides API definitions for CEF. Some extensions are implemented using Mojo and others use an older JSON-based format.

is the name of the API definition (e.g. 'alarms'). is the name of the class implementation (e.g. 'AlarmManager').

To add a new extension API implemented only in CEF ***:

1. Add libcef/common/extensions/api/.idl or .json file which defines the API.
2. Add .idl or .json to the 'schema_sources' list in libcef/common/extensions/api/BUILD.gn. Serialization code will be generated based on this list in step 4.
3. Add libcef/browser/extensions/api//_api.[h|cc] class implementation files and associated entries to the 'libcef_static' target in BUILD.gn.
4. Run the cef_create_projects script and build to generate the cef/libcef/common/extensions/api/.h file and other serialization code required by the extensions system.
5. Add an entry in the libcef/common/extensions/api/_*_features.json files if necessary [1].
6. Add an entry in the libcef/common/extensions/api/*_manifest_overlay.json files if necessary [2].
7. Call <class>::GetInstance(); or <class>Factory::GetFactoryInstance(); [3] from EnsureBrowserContextKeyedServiceFactoriesBuilt in libcef/browser/extensions/browser_context_keyed_service_factories.cc.
8. Call DependsOn(<class>Factory::GetInstance()); from CefExtensionSystemFactory::CefExtensionSystemFactory in libcef/browser/extensions/extension_system_factory.cc if necessary [3].

*** Note that CEF does not currently expose its own Mojo APIs. Related code is commented out in: cef/BUILD.gn cef/libcef/common/extensions/api/BUILD.gn CefExtensionsBrowserClient::RegisterExtensionFunctions CefExtensionsClient::IsAPISchemaGenerated CefExtensionsClient::GetAPISchema

To add a new extension API implemented in Chrome:

1. Register the API in libcef/browser/extensions/chrome_api_registration.cc
2. Perform steps 5 through 8 above.

See https://www.chromium.org/developers/design-documents/mojo for more information.

[1] A feature can optionally express requirements for where it can be accessed. See the _api_features.json and permission_features.json files for additional details. For Chrome extensions this should match the definitions in the chrome/common/extensions/api/*_features.json files.

[2] Service Manifest InterfaceProviderSpecs control interfaces exposed between processes. Mojo interfaces exposed at the frame level are controlled by the "navigation:frame" dictionary. Those exposed at the process level are controlled by the "service_manager:connector" dictionary. Failure to specify this correctly may result in a console error like the following:

  InterfaceProviderSpec "navigation:frame" prevented service:
  service:content_renderer from binding interface:
  mojom::Foo exposed by: service:content_browser

[3] Some Mojo APIs use singleton Factory objects that create a one-to-one relationship between a service and a BrowserContext. This is used primarily to control shutdown/destruction order and implementors must explicitly state which services are depended on. See comments in components/keyed_service/content/browser_context_keyed_service_factory.h for additional details.