Adding crash utilities to chromecast/crash.

chromecast/crash/app_state_tracker.cc

Index: chromecast/crash/app_state_tracker.cc
diff --git a/chromecast/crash/app_state_tracker.cc b/chromecast/crash/app_state_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b563ece66cdb1c5993fe6ca720881ab07d98eda9
--- /dev/null
+++ b/chromecast/crash/app_state_tracker.cc
@@ -0,0 +1,63 @@
+// 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 "chromecast/crash/app_state_tracker.h"
+
+#include "base/lazy_instance.h"
+#include "chromecast/crash/cast_crash_keys.h"
+
+namespace {
+
+struct CurrentAppState {
+  std::string previous_app;
+  std::string current_app;
+  std::string last_launched_app;
+};
+
+base::LazyInstance<CurrentAppState> g_app_state = LAZY_INSTANCE_INITIALIZER;
+
+CurrentAppState* GetAppState() {
+  return g_app_state.Pointer();
+}
+
+}  // namespace
+
+namespace chromecast {
+
+// static
+std::string AppStateTracker::GetLastLaunchedApp() {
+  return GetAppState()->last_launched_app;
+}
+
+// static
+std::string AppStateTracker::GetCurrentApp() {
+  return GetAppState()->current_app;
+}
+
+// static
+std::string AppStateTracker::GetPreviousApp() {
+  return GetAppState()->previous_app;
+}
+
+// static
+void AppStateTracker::SetLastLaunchedApp(const std::string& app_id) {
+  GetAppState()->last_launched_app = app_id;
+
+  // TODO(slan): Currently SetCrashKeyValue is a no-op on chromecast until

[gunsch, 2015/06/12 00:37:09]

This would be a pretty exciting follow-up, btw. We do this in a really
roundabout way for Chromecast, IIRC.

[slan, 2015/06/15 17:01:45]

b/21815373

+  // we add call to InitCrashKeys
+  base::debug::SetCrashKeyValue(crash_keys::kLastApp, app_id);
+}
+
+// static
+void AppStateTracker::SetCurrentApp(const std::string& app_id) {
+  CurrentAppState* app_state = GetAppState();
+  app_state->previous_app = app_state->current_app;
+  app_state->current_app = app_id;
+
+  base::debug::SetCrashKeyValue(crash_keys::kCurrentApp, app_id);
+  base::debug::SetCrashKeyValue(crash_keys::kPreviousApp,
+                                app_state->previous_app);
+}
+
+}  // namespace chromecast