Adding crash utilities to chromecast/crash.

chromecast/crash/app_state_tracker.h

Index: chromecast/crash/app_state_tracker.h
diff --git a/chromecast/crash/app_state_tracker.h b/chromecast/crash/app_state_tracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..f8a17443ed550be6c08b5900b6abce6f8e7155bc
--- /dev/null
+++ b/chromecast/crash/app_state_tracker.h
@@ -0,0 +1,26 @@
+// 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.
+
+#ifndef CHROMECAST_CRASH_APP_STATE_TRACKER_H_
+#define CHROMECAST_CRASH_APP_STATE_TRACKER_H_
+
+#include <string>
+
+namespace chromecast {
+
+class AppStateTracker {
+ public:
+  // Sets current app state.
+  static void SetLastLaunchedApp(const std::string& app_id);
+  static void SetCurrentApp(const std::string& app_id);
+
+  // Get current app state
+  static std::string GetLastLaunchedApp();
+  static std::string GetCurrentApp();
+  static std::string GetPreviousApp();
+};
+
+}  // namespace chromecast
+
+#endif  // CHROMECAST_CRASH_APP_STATE_TRACKER_H_