Bug 719240 - Delay sending touchmove events until touches have moved a minimum distance. r=mfinkle

mobile/android/base/gfx/LayerController.java

@@ -112,6 +112,7 @@ public class LayerController {
     private boolean allowDefaultActions = true;
     private Timer allowDefaultTimer =  null;
     private boolean inTouchSession = false;
+    private PointF initialTouchLocation = null;
 
     public LayerController(Context context) {
         mContext = context;
@@ -362,7 +363,9 @@ public class LayerController {
      */
     public boolean onTouchEvent(MotionEvent event) {
         int action = event.getAction();
+        PointF point = new PointF(event.getX(), event.getY());
         if ((action & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_DOWN) {
+            initialTouchLocation = point;
             post(new Runnable() {
                 public void run() {
                     mView.clearEventQueue();
@@ -371,6 +374,14 @@ public class LayerController {
             });
         }
 
+        if (initialTouchLocation != null && (action & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_MOVE) {
+            if (PointUtils.subtract(point, initialTouchLocation).length() > PanZoomController.PAN_THRESHOLD * 240) {
+                initialTouchLocation = null;
+            } else {
+                return !allowDefaultActions;
+            }
+        }
+
         if (mOnTouchListener != null)
             mOnTouchListener.onTouch(mView, event);
 

mobile/android/base/ui/PanZoomController.java

@@ -79,7 +79,7 @@ public class PanZoomController
     private static final float FLING_STOPPED_THRESHOLD = 0.1f;
     // The distance the user has to pan before we recognize it as such (e.g. to avoid
     // 1-pixel pans between the touch-down and touch-up of a click). In units of inches.
-    private static final float PAN_THRESHOLD = 0.1f;
+    public static final float PAN_THRESHOLD = 0.1f;
     // Angle from axis within which we stay axis-locked
     private static final double AXIS_LOCK_ANGLE = Math.PI / 6.0; // 30 degrees
     // The maximum amount we allow you to zoom into a page