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. 'streams_private'). is the name of the class implementation (e.g. 'StreamsPrivateAPI'). 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 `::GetInstance();` or `Factory::GetFactoryInstance();` [3] from EnsureBrowserContextKeyedServiceFactoriesBuilt in libcef/browser/extensions/browser_context_keyed_service_factories.cc. 8. Call `DependsOn(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.