content::BrowserContext* browser_context,

const std::string& mime_type) {

auto map = GetMimeTypeToExtensionIdMap(browser_context);

auto it = map.find(mime_type);

if (it != map.end())

return it->second;

return std::string();

content::BrowserContext* browser_context) {

base::flat_map<std::string, std::string> mime_type_to_extension_id_map;

#if BUILDFLAG(ENABLE_EXTENSIONS)

std::vector<std::string> allowed_extension_ids =

MimeTypesHandler::GetMIMETypeAllowlist();

// Go through the white-listed extensions and try to use them to intercept

// the URL request.

for (const std::string& extension_id : allowed_extension_ids) {

const extensions::Extension* extension =

extensions::ExtensionRegistry::Get(browser_context)

->enabled_extensions()

.GetByID(extension_id);

// The white-listed extension may not be installed, so we have to nullptr

// check |extension|.

if (!extension) {

continue;

}

if (MimeTypesHandler* handler = MimeTypesHandler::GetHandler(extension)) {

for (const auto& supported_mime_type : handler->mime_type_set()) {

DCHECK(!base::Contains(mime_type_to_extension_id_map,

supported_mime_type));

mime_type_to_extension_id_map[supported_mime_type] = extension_id;

}

}

}

#endif

return mime_type_to_extension_id_map;