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

extensions/browser/api/document_scan/document_scan_api.h

Index: extensions/browser/api/document_scan/document_scan_api.h
diff --git a/extensions/browser/api/document_scan/document_scan_api.h b/extensions/browser/api/document_scan/document_scan_api.h
index 806d7688d670684034d2d1eb8d96d9ee5f48b377..e2d1a186c37de1fa917f7f4db23997016ab833e9 100644
--- a/extensions/browser/api/document_scan/document_scan_api.h
+++ b/extensions/browser/api/document_scan/document_scan_api.h
@@ -15,7 +15,7 @@
 
 namespace extensions {
 
-namespace core_api {
+namespace api {
 
 class DocumentScanScanFunction : public AsyncApiFunction {
  public:
@@ -47,7 +47,7 @@ class DocumentScanScanFunction : public AsyncApiFunction {
   DISALLOW_COPY_AND_ASSIGN(DocumentScanScanFunction);
 };
 
-}  // namespace core_api
+}  // namespace api
 
 }  // namespace extensions