Screensaver at login screen.

chrome/browser/ui/views/screensaver_extension_dialog.cc

+// Copyright (c) 2012 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/ui/views/screensaver_extension_dialog.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/sessions/restore_tab_helper.h"
+#include "chrome/browser/ui/views/extensions/extension_dialog.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_file_util.h"
+
+using content::BrowserThread;
+
+namespace {
+
+ScreensaverExtensionDialog* g_instance = NULL;
+
+}  // namespace
+
+namespace browser {
+
+void ShowScreensaverDialog() {
+  ScreensaverExtensionDialog::ShowScreensaverDialog();
+}
+
+void CloseScreensaverDialog() {
+  ScreensaverExtensionDialog::CloseScreensaverDialog();
+}
+
+}  // namespace browser
+
+// static
+void ScreensaverExtensionDialog::ShowScreensaverDialog() {
+  if (g_instance)

[Yoyo Zhou, 2012/02/24 21:51:05]

So once the screensaver is closed, it will never appear again (even if no one
logs in)?

[rkc, 2012/02/25 02:14:02]

This is incorrect code, fixed.

Done.

+    return;
+
+  g_instance = new ScreensaverExtensionDialog();
+  g_instance->Show();
+}
+
+// static
+void ScreensaverExtensionDialog::CloseScreensaverDialog() {
+  if (g_instance)
+    g_instance->Close();
+}
+
+ScreensaverExtensionDialog::ScreensaverExtensionDialog()
+    : screensaver_extension_(NULL) {
+}
+
+void ScreensaverExtensionDialog::LoadExtension() {
+  std::string error;

[sky, 2012/02/24 05:03:53]

If this needs to run on a specific thread, DCHECK that.
This is also error prone because you're using the same object on multiple
threads. I would rather see a standalone function that loads the extension and
callback with the loaded extension.

[rkc, 2012/02/25 02:14:02]

Done.

+  std::string extension_path = CommandLine::ForCurrentProcess()->
+      GetSwitchValueASCII(switches::kKioskModeScreensaverPath);
+  screensaver_extension_ = extension_file_util::LoadExtension(

[Yoyo Zhou, 2012/02/24 21:51:05]

This should probably call Extension::Create, but see comment below about
ComponentLoader.

[rkc, 2012/02/25 02:14:02]

Answered below.

+      FilePath(extension_path),
+      Extension::COMPONENT,
+      Extension::NO_FLAGS,
+      &error);
+
+  if (!screensaver_extension_) {
+    LOG(ERROR) << "Could not load screensaver extension from: " <<
+        extension_path;
+    return;
+  }
+
+  BrowserThread::PostTask(BrowserThread::UI,
+                          FROM_HERE,
+                          base::Bind(
+                              &ScreensaverExtensionDialog::Show,
+                              base::Unretained(this)));
+
+}
+
+void ScreensaverExtensionDialog::Show() {
+  if (!screensaver_extension_) {
+    BrowserThread::PostTask(BrowserThread::FILE,
+                            FROM_HERE,
+                            base::Bind(
+                                &ScreensaverExtensionDialog::LoadExtension,
+                                base::Unretained(this)));
+    return;
+  }
+
+  GURL screensaver_url("chrome-extension://" +

[sky, 2012/02/24 05:03:53]

Surely there must be constants for this sort of thing around?

[Yoyo Zhou, 2012/02/24 21:51:05]

Use Extension::GetResourceURL for this.

[rkc, 2012/02/25 02:14:02]

Done.

[rkc, 2012/02/25 02:14:02]

Done.

+                       screensaver_extension_->id() +
+                       "/background.html");

[Yoyo Zhou, 2012/02/24 21:51:05]

Why hardcode this? Also, there seems to be no reason it needs to be a background
page; it seems this is more of a packaged app.

[rkc, 2012/02/25 02:14:02]

Done.

+
+  Profile* default_profile = ProfileManager::GetDefaultProfile();

[Yoyo Zhou, 2012/02/24 21:51:05]

Are you sure this will be the correct profile? I'm not familiar with the login
screen profile situation.

[rkc, 2012/02/25 02:14:02]

This is the only profile available during login.

For the next iteration, we may be creating our own temp profile and adding the
extension to do that and using that instead for security reasons - but for now,
this should work fine for us.

+  if (default_profile->GetExtensionService()->AddExtension(

[Yoyo Zhou, 2012/02/24 21:51:05]

If this is a component extension it should use ComponentLoader. Perhaps even
ComponentLoader::Load.

[rkc, 2012/02/25 02:14:02]

This isn't a component extension but we need it loaded as one. If we don't load
it as a component extension, the extension won't load on the login screen (loads
everywhere else just fine).

+          screensaver_extension_)) {
+    extension_dialog_ = ExtensionDialog::ShowFullscreen(screensaver_url,
+                                                        default_profile,
+                                                        string16(),
+                                                        this);
+  } else {
+    LOG(ERROR) << "Couldn't add screensaver extension to profile.";
+  }
+}
+
+void ScreensaverExtensionDialog::Close() {
+  extension_dialog_->Close();
+  extension_dialog_ = NULL;
+}
+
+ScreensaverExtensionDialog::~ScreensaverExtensionDialog() {
+  if (extension_dialog_)

[sky, 2012/02/24 05:03:53]

Who deletes this class?

[rkc, 2012/02/25 02:14:02]

I believe extension_dialog_ deletes itself by calling Release on itself when
closing.

+    extension_dialog_->ObserverDestroyed();
+}
+
+void ScreensaverExtensionDialog::ExtensionDialogClosing(
+    ExtensionDialog* dialog) {
+  // Release our reference to the dialog to allow it to close.
+  extension_dialog_ = NULL;
+}
+
+void ScreensaverExtensionDialog::ExtensionTerminated(
+    ExtensionDialog* dialog) {
+  MessageLoop::current()->PostTask(FROM_HERE,

[sky, 2012/02/24 05:03:53]

Why does this need to be delayed?

[rkc, 2012/02/25 02:14:02]

If we don't delay this, the extension hasn't actually finished terminating,
landing us in the middle of a state which causes our extension to not reload
since it hasn't actually been unloaded yet.

This is a bit of a hack but currently there are no good solutions around this -
I've discussed this with yoz@ and aa@ when implementing reload on crash for the
select_file_dialog_extension.

The correct solution will be not even needing to reload the extension but that
is not working yet for views hosted extensions.

+      base::Bind(&ScreensaverExtensionDialog::ReloadAndShow,
+          base::Unretained(this)));
+  dialog->Close();
+}
+
+void ScreensaverExtensionDialog::ReloadAndShow() {
+  ProfileManager::GetDefaultProfile()->GetExtensionService()->ReloadExtension(
+      screensaver_extension_->id());
+
+  Show();
+}