athena: Use ActivityList where appropriate, and fix AppActivity tests.

athena/content/app_activity_unittest.cc

Index: athena/content/app_activity_unittest.cc
diff --git a/athena/content/app_activity_unittest.cc b/athena/content/app_activity_unittest.cc
index 266b940fd4e9ae817b4d98feb64ffd8aec80c50a..56e9d41de85f3e37b38e98ad82863307bd3da5a3 100644
--- a/athena/content/app_activity_unittest.cc
+++ b/athena/content/app_activity_unittest.cc
@@ -34,57 +34,22 @@ class TestAppActivity : public AppActivity {
  public:
   explicit TestAppActivity(const std::string& app_id)
       : AppActivity(app_id),
-        view_(new views::View()),
-        current_state_(ACTIVITY_VISIBLE) {
-    app_activity_registry_ =
-        AppRegistry::Get()->GetAppActivityRegistry(app_id, nullptr);
-    app_activity_registry_->RegisterAppActivity(this);
+        view_(new views::View()) {
   }
   ~TestAppActivity() override {
-    app_activity_registry_->UnregisterAppActivity(this);
   }
 
   AppActivityRegistry* app_activity_registry() {
-    return app_activity_registry_;
-  }
-
-  // Activity:
-  ActivityViewModel* GetActivityViewModel() override { return this; }
-  void SetCurrentState(Activity::ActivityState state) override {
-    current_state_ = state;
-    if (state == ACTIVITY_UNLOADED)
-      app_activity_registry_->Unload();
-  }
-  ActivityState GetCurrentState() override { return current_state_; }
-  bool IsVisible() override { return true; }
-  ActivityMediaState GetMediaState() override {
-    return Activity::ACTIVITY_MEDIA_STATE_NONE;
-  }
-  aura::Window* GetWindow() override {
-    return view_->GetWidget() ? view_->GetWidget()->GetNativeWindow() : nullptr;
+    return AppActivity::app_activity_registry();
   }
 
   // ActivityViewModel:
-  void Init() override {}
-  SkColor GetRepresentativeColor() const override { return 0; }
-  base::string16 GetTitle() const override { return title_; }
-  bool UsesFrame() const override { return true; }
   views::View* GetContentsView() override { return view_; }
-  gfx::ImageSkia GetOverviewModeImage() override { return gfx::ImageSkia(); }
 
  private:
-  // If known the registry which holds all activities for the associated app.
-  AppActivityRegistry* app_activity_registry_;
-
-  // The title of the activity.
-  base::string16 title_;
-
   // Our view.
   views::View* view_;
 
-  // The current state for this activity.
-  ActivityState current_state_;
-
   DISALLOW_COPY_AND_ASSIGN(TestAppActivity);
 };
 
@@ -149,6 +114,7 @@ class AppActivityTest : public AthenaTestBase {
   // A function to create an Activity.
   TestAppActivity* CreateAppActivity(const std::string& app_id) {
     TestAppActivity* activity = new TestAppActivity(app_id);
+    activity->SetCurrentState(Activity::ACTIVITY_VISIBLE);
     ActivityManager::Get()->AddActivity(activity);
     return activity;
   }
@@ -158,16 +124,15 @@ class AppActivityTest : public AthenaTestBase {
     RunAllPendingInMessageLoop();
   }
 
-  // Get the position of the activity in the navigation history.
+  // Get the position of the activity in the navigation history (the position
+  // of the oldest activity is 0).
   int GetActivityPosition(Activity* activity) {
-    aura::Window* window = activity->GetActivityViewModel()->GetContentsView()
-                               ->GetWidget()->GetNativeWindow();
-    aura::Window::Windows windows = activity->GetWindow()->parent()->children();
-    for (size_t i = 0; i < windows.size(); i++) {
-      if (windows[i] == window)
-        return i;
-    }
-    return -1;
+    const ActivityList& activity_list =
+        ActivityManager::Get()->GetActivityList();
+    ActivityList::const_iterator iter =
+        std::find(activity_list.begin(), activity_list.end(), activity);
+    return (iter == activity_list.end()) ? -1
+                                         : (activity_list.end() - iter - 1);
   }
 
   // To avoid interference of the ResourceManager in these AppActivity