Add a function triggering extension installed to ExtensionRegistryObserver

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 5880add25e63307af4691dae2e4bc98bdbcd7b99..d127e0a0ee252f605307e0a6f18f9b45f61594c2 100644
--- a/extensions/browser/extension_registry_observer.h
+++ b/extensions/browser/extension_registry_observer.h
@@ -33,6 +33,12 @@ class ExtensionRegistryObserver {
   virtual void OnExtensionUnloaded(content::BrowserContext* browser_context,
                                    const Extension* extension,
                                    UnloadedExtensionInfo::Reason reason) {}
+
+  // Called after an extension is installed. The extension will exclusively
+  // exists in any of the ExtensionRegistry sets (enabled, disabled, etc.).

[not at google - send to devlin, 2014/05/14 18:17:50]

How about the second sentence: The extension will be in exactly one of the
ExtensionRegistry sets.

[limasdf, 2014/05/16 01:02:35]

Done. Thank you.

+  virtual void OnExtensionInstalled(content::BrowserContext* browser_context,
+                                    const Extension* extension,
+                                    InstalledExtensionInfo info) {}

[not at google - send to devlin, 2014/05/14 18:17:50]

we should unwrap the arguments of InstalledExtensionInfo in the same way we did
for Unload. That is,
- const Extension* extension
- bool is_update
- const std::string& old_name

[limasdf, 2014/05/16 01:02:35]

Done.

 };
 
 }  // namespace extensions