Observe adding external extensions via windows registry.

chrome/browser/extensions/external_registry_loader_win.h

Index: chrome/browser/extensions/external_registry_loader_win.h
diff --git a/chrome/browser/extensions/external_registry_loader_win.h b/chrome/browser/extensions/external_registry_loader_win.h
index 25de48dfb92a9ceba1c2581c8d256e08f203cb88..fca0c5701f6474581af3f0251aa8686f44b116c4 100644
--- a/chrome/browser/extensions/external_registry_loader_win.h
+++ b/chrome/browser/extensions/external_registry_loader_win.h
@@ -7,6 +7,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/win/registry.h"
 #include "chrome/browser/extensions/external_loader.h"
 
 namespace extensions {
@@ -23,7 +24,14 @@ class ExternalRegistryLoader : public ExternalLoader {
 
   ~ExternalRegistryLoader() override {}
 
+  scoped_ptr<base::DictionaryValue> LoadPrefsOnFileThread();
   void LoadOnFileThread();
+  void CompleteLoadAndStartWatchingRegistry();
+  void UpdatePrefsOnFileThread();
+  void OnRegistryKeyChanged(base::win::RegKey* key);
+
+  base::win::RegKey hklm_key_;
+  base::win::RegKey hkcu_key_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalRegistryLoader);
 };