Fix race condition on kiosk app launch.

The previous code would fail for the case of the app window already
present before the observer gets registered.

BUG=chromium:343540

Review URL: https://codereview.chromium.org/163493002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251088 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/login/app_launch_controller.cc

@@ -4,10 +4,14 @@
 
 #include "chrome/browser/chromeos/login/app_launch_controller.h"
 
+#include "apps/shell_window.h"
 #include "apps/shell_window_registry.h"
+#include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/json/json_file_value_serializer.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
@@ -53,10 +57,21 @@ AppLaunchController::ReturnBoolCallback*
 class AppLaunchController::AppWindowWatcher
     : public apps::ShellWindowRegistry::Observer {
  public:
-  explicit AppWindowWatcher(AppLaunchController* controller)
+  explicit AppWindowWatcher(AppLaunchController* controller,
+                            const std::string& app_id)
     : controller_(controller),
-      window_registry_(apps::ShellWindowRegistry::Get(controller->profile_)) {
-    window_registry_->AddObserver(this);
+      app_id_(app_id),
+      window_registry_(apps::ShellWindowRegistry::Get(controller->profile_)),
+      weak_factory_(this) {
+    if (!window_registry_->GetShellWindowsForApp(app_id).empty()) {
+      base::MessageLoop::current()->PostTask(
+          FROM_HERE,
+          base::Bind(&AppWindowWatcher::NotifyAppWindowCreated,
+                     weak_factory_.GetWeakPtr()));
+      return;
+    } else {
+      window_registry_->AddObserver(this);
+    }
   }
   virtual ~AppWindowWatcher() {
     window_registry_->RemoveObserver(this);
@@ -65,17 +80,23 @@ class AppLaunchController::AppWindowWatcher
  private:
   // apps::ShellWindowRegistry::Observer overrides:
   virtual void OnShellWindowAdded(apps::ShellWindow* shell_window) OVERRIDE {
-    if (controller_) {
-      controller_->OnAppWindowCreated();
-      controller_= NULL;
+    if (shell_window->extension_id() == app_id_) {
+      window_registry_->RemoveObserver(this);
+      NotifyAppWindowCreated();
     }
   }
   virtual void OnShellWindowIconChanged(
       apps::ShellWindow* shell_window) OVERRIDE {}
   virtual void OnShellWindowRemoved(apps::ShellWindow* shell_window) OVERRIDE {}
 
+  void NotifyAppWindowCreated() {
+    controller_->OnAppWindowCreated();
+  }
+
   AppLaunchController* controller_;
+  std::string app_id_;
   apps::ShellWindowRegistry* window_registry_;
+  base::WeakPtrFactory<AppWindowWatcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AppWindowWatcher);
 };
@@ -368,7 +389,7 @@ void AppLaunchController::OnLaunchSucceeded() {
       AppLaunchSplashScreenActor::APP_LAUNCH_STATE_WAITING_APP_WINDOW);
 
   DCHECK(!app_window_watcher_);
-  app_window_watcher_.reset(new AppWindowWatcher(this));
+  app_window_watcher_.reset(new AppWindowWatcher(this, app_id_));
 }
 
 void AppLaunchController::OnLaunchFailed(KioskAppLaunchError::Error error) {