Add new public attribute mPointerId to PointerTracker

It is easier to track each pointer if a PointerTracker object keeps
its pointer id.

Bug: 2910379
Change-Id: If3e3b0cf3d834d22302598f4d85d54c9a4ce92ba

java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java

@@ -774,7 +774,6 @@ public class LatinKeyboardBaseView extends View implements View.OnClickListener,
         if (DEBUG) {
             if (mShowTouchPoints) {
                 for (PointerTracker tracker : mPointerTrackers) {
-                    if (tracker == null) continue;
                     int startX = tracker.getStartX();
                     int startY = tracker.getStartY();
                     int lastX = tracker.getLastX();
@@ -1047,7 +1046,7 @@ public class LatinKeyboardBaseView extends View implements View.OnClickListener,
         // Create pointer trackers until we can get 'id+1'-th tracker, if needed.
         for (int i = pointers.size(); i <= id; i++) {
             final PointerTracker tracker =
-                new PointerTracker(mHandler, mKeyDetector, this);
+                new PointerTracker(i, mHandler, mKeyDetector, this);
             if (keys != null)
                 tracker.setKeyboard(keys, mDebounceHysteresis);
             if (listener != null)

java/src/com/android/inputmethod/latin/PointerTracker.java

@@ -32,6 +32,8 @@ public class PointerTracker {
         public boolean isMiniKeyboardOnScreen();
     }
 
+    public final int mPointerId;
+
     // Timing constants
     private static final int REPEAT_START_DELAY = 400;
     /* package */  static final int REPEAT_INTERVAL = 50; // ~20 keys per second
@@ -77,9 +79,10 @@ public class PointerTracker {
     // pressed key
     private int mPreviousKey = NOT_A_KEY;
 
-    public PointerTracker(UIHandler handler, KeyDetector keyDetector, UIProxy proxy) {
+    public PointerTracker(int id, UIHandler handler, KeyDetector keyDetector, UIProxy proxy) {
         if (proxy == null || handler == null || keyDetector == null)
             throw new NullPointerException();
+        mPointerId = id;
         mProxy = proxy;
         mHandler = handler;
         mKeyDetector = keyDetector;