[Extensions] Migrate ExtensionInstallPrompt::Delegate to be a callback

chrome/browser/extensions/api/developer_private/show_permissions_dialog_helper.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/developer_private/show_permissions_dialog_helper.h"
 
 #include <utility>
 
 #include "apps/app_load_service.h"
 #include "apps/saved_files_service.h"
@@ skipping 65 matching lines @@
   if (extension->permissions_data()->HasAPIPermission(APIPermission::kUsb)) {
     retained_device_messages =
         DevicePermissionsManager::Get(profile_)
             ->GetPermissionMessageStrings(extension_id_);
   }
   scoped_ptr<ExtensionInstallPrompt::Prompt> prompt(
       new ExtensionInstallPrompt::Prompt(
           ExtensionInstallPrompt::POST_INSTALL_PERMISSIONS_PROMPT));
   prompt->set_retained_files(retained_file_paths);
   prompt->set_retained_device_messages(retained_device_messages);
-  prompt_->ShowDialog(this, extension, nullptr, std::move(prompt),
-                      ExtensionInstallPrompt::GetDefaultShowDialogCallback());
+  // Unretained() is safe because this class manages its own lifetime and
+  // deletes itself in OnInstallPromptDone().

[asargent_no_longer_on_chrome, 2015/12/31 00:45:56]

also safe because it owns the prompt and so should be guaranteed to outlive it -
not sure if that's worth mentioning or not

[Devlin, 2016/01/04 22:59:22]

But that's part of the point in this change - it's not necessarily safe just
because the prompt is owned, because the prompt here is the
ExtensionInstallPrompt, whose lifetime is completely independent from the
ExtensionInstallPromptView/cocoa equivalent.  Just because this owns the prompt
doesn't mean that the install prompt view couldn't outlive this.

+  prompt_->ShowDialog(
+      base::Bind(&ShowPermissionsDialogHelper::OnInstallPromptDone,
+                 base::Unretained(this)),
+      extension, nullptr, std::move(prompt),
+      ExtensionInstallPrompt::GetDefaultShowDialogCallback());
 }
 
-// This is called when the user clicks "Revoke File Access."
-void ShowPermissionsDialogHelper::InstallUIProceed() {
-  const Extension* extension =
-      ExtensionRegistry::Get(profile_)->GetExtensionById(
-          extension_id_, ExtensionRegistry::EVERYTHING);
+void ShowPermissionsDialogHelper::OnInstallPromptDone(
+    ExtensionInstallPrompt::Result result) {
+  if (result == ExtensionInstallPrompt::Result::ACCEPTED) {
+    // This is true when the user clicks "Revoke File Access."
+    const Extension* extension =
+        ExtensionRegistry::Get(profile_)
+            ->GetExtensionById(extension_id_, ExtensionRegistry::EVERYTHING);
 
-  if (extension)
-    apps::SavedFilesService::Get(profile_)->ClearQueue(extension);
-  apps::AppLoadService::Get(profile_)
-      ->RestartApplicationIfRunning(extension_id_);
+    if (extension)
+      apps::SavedFilesService::Get(profile_)->ClearQueue(extension);
+    apps::AppLoadService::Get(profile_)
+        ->RestartApplicationIfRunning(extension_id_);
+  }
 
   on_complete_.Run();
-
   delete this;
 }
 
-void ShowPermissionsDialogHelper::InstallUIAbort(bool user_initiated) {
-  on_complete_.Run();
-
-  delete this;
-}
-
 }  // namespace extensions