Remove InstallTracker's extension installed, uninstalled observers.

chrome/browser/extensions/install_observer.h

Index: chrome/browser/extensions/install_observer.h
diff --git a/chrome/browser/extensions/install_observer.h b/chrome/browser/extensions/install_observer.h
index fb11ae0cce0ff5e36fdebb41bcac6655a90b8672..0886cc33f4f827dd838c93510b4fe39741932856 100644
--- a/chrome/browser/extensions/install_observer.h
+++ b/chrome/browser/extensions/install_observer.h
@@ -59,13 +59,8 @@ class InstallObserver {
   // Called if the extension fails to install.
   virtual void OnInstallFailure(const std::string& extension_id) {}
 
-  // Called if the installation succeeds.
-  virtual void OnExtensionInstalled(const Extension* extension) {}
-
-  // Called when an extension is [Uninstalled] or an app is
-  // installed to the app list. These are simply forwarded from the
-  // chrome::NOTIFICATIONs.
-  virtual void OnExtensionUninstalled(const Extension* extension) {}
+  // Called when an extension or an app is installed to the app list. These are
+  // simply forwarded from the chrome::NOTIFICATIONs.
   virtual void OnDisabledExtensionUpdated(const Extension* extension) {}
   virtual void OnAppInstalledToAppList(const std::string& extension_id) {}