Generate all extension schema namespaces as "api" and instead vary the generated bundle names.

extensions/common/cast/cast_cert_validator.cc

Index: extensions/common/cast/cast_cert_validator.cc
diff --git a/extensions/common/cast/cast_cert_validator.cc b/extensions/common/cast/cast_cert_validator.cc
index d48325796a65da4b127e42bcf6256809b7b6e110..cdd803aecf4ad2e75e44b3771eabef33b0b9c0d7 100644
--- a/extensions/common/cast/cast_cert_validator.cc
+++ b/extensions/common/cast/cast_cert_validator.cc
@@ -7,7 +7,7 @@
 #include "extensions/browser/api/cast_channel/cast_auth_ica.h"
 
 namespace extensions {
-namespace core_api {
+namespace api {
 namespace cast_crypto {
 
 VerificationResult::VerificationResult()
@@ -29,10 +29,10 @@ VerificationResult::VerificationResult(const std::string& in_error_message,
 
 bool SetTrustedCertificateAuthoritiesForTest(const std::string& keys,
                                              const std::string& signature) {
-  return extensions::core_api::cast_channel::SetTrustedCertificateAuthorities(
+  return extensions::api::cast_channel::SetTrustedCertificateAuthorities(
       keys, signature);
 }
 
 }  // namespace cast_crypto
-}  // namespace core_api
+}  // namespace api
 }  // namespace extensions