Don't consider shutdown acknowledgement for external extensions

chrome/browser/extensions/external_install_ui.cc

Index: chrome/browser/extensions/external_install_ui.cc
diff --git a/chrome/browser/extensions/external_install_ui.cc b/chrome/browser/extensions/external_install_ui.cc
index 18321849b877eba83b28b2e7855622112b2822da..dc0abc4c292baa052c213a15bf6a57052c555db0 100644
--- a/chrome/browser/extensions/external_install_ui.cc
+++ b/chrome/browser/extensions/external_install_ui.cc
@@ -340,7 +340,13 @@ void ExternalInstallDialogDelegate::InstallUIProceed() {
 
 void ExternalInstallDialogDelegate::InstallUIAbort(bool user_initiated) {
   const Extension* extension = NULL;
-  if (service_weak_.get() &&
+
+  // Uninstall the extension if the abort was user initiated (and not, e.g., the
+  // result of the window closing).
+  // Otherwise, the extension will remain installed, but unacknowledged, so it
+  // will be prompted again.
+  if (user_initiated &&
+      service_weak_.get() &&
       (extension = service_weak_->GetInstalledExtension(extension_id_))) {
     service_weak_->UninstallExtension(extension_id_, false, NULL);
   }