Invoke callback from WebstoreInstaller when installation is fully complete

extensions/browser/extension_registry_observer.h

Index: extensions/browser/extension_registry_observer.h
diff --git a/extensions/browser/extension_registry_observer.h b/extensions/browser/extension_registry_observer.h
index 8aa0d079d14e05b5b8d750ab3a0d68a52dd14477..d0b10f3865b410bcb3a8eb7fbbf805bde2651608 100644
--- a/extensions/browser/extension_registry_observer.h
+++ b/extensions/browser/extension_registry_observer.h
@@ -59,7 +59,13 @@ class ExtensionRegistryObserver {
       bool from_ephemeral,
       const std::string& old_name) {}
 
-  // Called after an extension is uninstalled. The extension no longer exsit in
+  // Called when the installation of |extension| is complete. At this point the
+  // extension is tracked in one of the ExtensionRegistry sets, but is not
+  // necessarily enabled.

[asargent_no_longer_on_chrome, 2014/06/11 18:27:54]

Would it be helpful to pass the enabled/disabled state as an additional
parameter?

[tmdiep, 2014/06/11 22:56:18]

I think maybe not for this notification - it's for observers who want to know
when the entire installation process is complete. Observers that do things when
an extension is enabled listen for OnLoaded.

+  virtual void OnExtensionInstalled(content::BrowserContext* browser_context,
+                                    const Extension* extension) {}
+
+  // Called after an extension is uninstalled. The extension no longer exists in
   // any of the ExtensionRegistry sets (enabled, disabled, etc.).
   virtual void OnExtensionUninstalled(content::BrowserContext* browser_context,
                                       const Extension* extension) {}