Fire SystemMonitor::{RESUME,SUSPEND}_EVENT on Android.

base/android/java/src/org/chromium/base/ActivityStatus.java

Index: base/android/java/src/org/chromium/base/ActivityStatus.java
diff --git a/base/android/java/src/org/chromium/base/ActivityStatus.java b/base/android/java/src/org/chromium/base/ActivityStatus.java
index b80c1499675c12540e4f301f0ffe0e1e89520765..e728870a0e1e49e3d4f9b4e0d41e43333e7df886 100644
--- a/base/android/java/src/org/chromium/base/ActivityStatus.java
+++ b/base/android/java/src/org/chromium/base/ActivityStatus.java
@@ -25,24 +25,23 @@ public class ActivityStatus {
     // Current main activity, or null if none.
     private static Activity sActivity;
 
-    // Current main activity's state. This can be set even if sActivity
-    // is null, to simplify unit testing.
+    // Current main activity's state. This can be set even if sActivity is null, to simplify unit
+    // testing.
     private static int sActivityState;
 
-    // Current activity instance, or null.
-    private static ActivityStatus sInstance;
+    private static final ArrayList<StateListener> sStateListeners = new ArrayList<StateListener>();
 
-    // List of pause/resume listeners.
-    private final ArrayList<Listener> mListeners;
-
-    // List of state listeners.
-    private final ArrayList<StateListener> mStateListeners;
-
-    protected ActivityStatus() {
-        mListeners = new ArrayList<Listener>();
-        mStateListeners = new ArrayList<StateListener>();
+    // Use this interface to listen to all state changes.
+    public interface StateListener {
+        /**
+         * Called when the activity's state changes.
+         * @param newState New activity state.
+         */
+        public void onActivityStateChange(int newState);
     }
 
+    private ActivityStatus() {}
+
     /**
      * Must be called by the main activity when it changes state.
      * @param activity Current activity.
@@ -53,76 +52,18 @@ public class ActivityStatus {
             sActivity = activity;
         }
         sActivityState = newState;
-        getInstance().changeState(newState);
-
-        if (newState == DESTROYED) {
-            sActivity = null;
-        }
-    }
-
-    private void changeState(int newState) {
-        for (StateListener listener : mStateListeners) {
+        for (StateListener listener : sStateListeners) {
             listener.onActivityStateChange(newState);
         }
-        if (newState == PAUSED || newState == RESUMED) {
-            boolean paused = (newState == PAUSED);
-            for (Listener listener : mListeners) {
-                listener.onActivityStatusChanged(paused);
-            }
-        }
-    }
-
-    // This interface can only be used to listen to PAUSED and RESUMED
-    // events. Deprecated, new code should use StateListener instead.
-    // TODO(digit): Remove once all users have switched to StateListener.
-    @Deprecated
-    public interface Listener {
-        /**
-         * Called when the activity is paused or resumed only.
-         * @param isPaused true if the activity is paused, false if not.
-         */
-        public void onActivityStatusChanged(boolean isPaused);
-    }
-
-    // Use this interface to listen to all state changes.
-    public interface StateListener {
-        /**
-         * Called when the activity's state changes.
-         * @param newState New activity state.
-         */
-        public void onActivityStateChange(int newState);
-    }
-
-    /**
-     * Returns the current ActivityStatus instance.
-     */
-    public static ActivityStatus getInstance() {
-        // Can only be called on the UI thread.
-        assert Looper.myLooper() == Looper.getMainLooper();
-        if (sInstance == null) {
-            sInstance = new ActivityStatus();
+        if (newState == DESTROYED) {
+            sActivity = null;
         }
-        return sInstance;
-    }
-
-    /**
-     * Indicates that the parent activity was paused.
-     */
-    public void onPause() {
-       changeState(PAUSED);
-    }
-
-    /**
-     * Indicates that the parent activity was resumed.
-     */
-    public void onResume() {
-        changeState(RESUMED);
     }
 
     /**
      * Indicates that the parent activity is currently paused.
      */
-    public boolean isPaused() {
+    public static boolean isPaused() {
         return sActivityState == PAUSED;
     }
 
@@ -137,35 +78,15 @@ public class ActivityStatus {
      * Returns the current main application activity's state.
      */
     public static int getState() {
-        // To simplify unit testing, don't check sActivity for null.
         return sActivityState;
     }
 
     /**
-     * Registers the given pause/resume listener to receive activity
-     * status updates. Use registerStateListener() instead.
-     * @param listener Listener to receive status updates.
-     */
-    public void registerListener(Listener listener) {
-        mListeners.add(listener);
-    }
-
-    /**
-     * Unregisters the given pause/resume listener from receiving activity
-     * status updates. Use unregisterStateListener() instead.
-     * @param listener Listener that doesn't want to receive status updates.
-     */
-    public void unregisterListener(Listener listener) {
-        mListeners.remove(listener);
-    }
-
-    /**
      * Registers the given listener to receive activity state changes.
      * @param listener Listener to receive state changes.
      */
     public static void registerStateListener(StateListener listener) {
-        ActivityStatus status = getInstance();
-        status.mStateListeners.add(listener);
+        sStateListeners.add(listener);
     }
 
     /**
@@ -173,7 +94,6 @@ public class ActivityStatus {
      * @param listener Listener that doesn't want to receive state changes.
      */
     public static void unregisterStateListener(StateListener listener) {
-        ActivityStatus status = getInstance();
-        status.mStateListeners.remove(listener);
+        sStateListeners.remove(listener);
     }
 }