QS: Inversion tile: Don't consider initial 0 setting trackable.

For usage tracking purposes, seeing a setting value of 1 is always
considered trackable.

However, only consider a setting value of 0 as trackable if we've
observed a change (from 1).  Avoids tracking a db update from null
to 0 (via settings cmd or a restore).

Bug: 18062541
Change-Id: Ic8413b1770040f9ef28041bbadb4e5fb62d1c014

packages/SystemUI/src/com/android/systemui/qs/SecureSetting.java

@@ -26,24 +26,26 @@ import com.android.systemui.statusbar.policy.Listenable;
 
 /** Helper for managing a secure setting. **/
 public abstract class SecureSetting extends ContentObserver implements Listenable {
+    private static final int DEFAULT = 0;
+
     private final Context mContext;
     private final String mSettingName;
 
     private boolean mListening;
     private int mUserId;
+    private int mObservedValue = DEFAULT;
 
-    protected abstract void handleValueChanged(int value);
+    protected abstract void handleValueChanged(int value, boolean observedChange);
 
     public SecureSetting(Context context, Handler handler, String settingName) {
         super(handler);
         mContext = context;
         mSettingName = settingName;
         mUserId = ActivityManager.getCurrentUser();
-        setListening(true);
     }
 
     public int getValue() {
-        return Secure.getIntForUser(mContext.getContentResolver(), mSettingName, 0, mUserId);
+        return Secure.getIntForUser(mContext.getContentResolver(), mSettingName, DEFAULT, mUserId);
     }
 
     public void setValue(int value) {
@@ -52,18 +54,23 @@ public abstract class SecureSetting extends ContentObserver implements Listenabl
 
     @Override
     public void setListening(boolean listening) {
+        if (listening == mListening) return;
         mListening = listening;
         if (listening) {
+            mObservedValue = getValue();
             mContext.getContentResolver().registerContentObserver(
                     Secure.getUriFor(mSettingName), false, this, mUserId);
         } else {
             mContext.getContentResolver().unregisterContentObserver(this);
+            mObservedValue = DEFAULT;
         }
     }
 
     @Override
     public void onChange(boolean selfChange) {
-        handleValueChanged(getValue());
+        final int value = getValue();
+        handleValueChanged(value, value != mObservedValue);
+        mObservedValue = value;
     }
 
     public void setUserId(int userId) {

packages/SystemUI/src/com/android/systemui/qs/tiles/ColorInversionTile.java

@@ -41,8 +41,10 @@ public class ColorInversionTile extends QSTile<QSTile.BooleanState> {
         mSetting = new SecureSetting(mContext, mHandler,
                 Secure.ACCESSIBILITY_DISPLAY_INVERSION_ENABLED) {
             @Override
-            protected void handleValueChanged(int value) {
-                mUsageTracker.trackUsage();
+            protected void handleValueChanged(int value, boolean observedChange) {
+                if (value != 0 || observedChange) {
+                    mUsageTracker.trackUsage();
+                }
                 if (mListening) {
                     handleRefreshState(value);
                 }