[Chromoting] Minor changes to TapGestureDetector

remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java

Index: remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java
diff --git a/remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java b/remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java
index 45dab790a2c3012a486115f42e55466289824cec..ccceb52b30a13aab505022821ed567254c06646a 100644
--- a/remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java
+++ b/remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java
@@ -42,10 +42,10 @@ public class TapGestureDetector {
     }
 
     /** The listener to which notifications are sent. */
-    private OnTapListener mListener;
+    private final OnTapListener mListener;

[Lambros, 2016/06/02 18:11:30]

Are you adding 'final' simply because this implementation doesn't modify it?

This isn't *logically* final. You could easily add a setListener() method
without breaking anything.

There is a small cost to adding 'final' (not just the extra typing and clutter).
The problem is that 'final' can discourage other developers from removing it,
which is why I prefer not to use it unnecessarily.

But I don't feel strongly, there are some benefits as well, and I'm not aware of
any style guidance.

[Hzj_jie, 2016/06/02 22:20:04]

In my opinion -- it's similar as the 'final' of SelfRemovableParameterRunnable
-- it would be better to 'final' it unless we need to make it not 'final'. For
these fields, finalizing them can help the readers to understand their
references won't be changed during the lifetime of this instance.

 
     /** Handler used for posting tasks to be executed in the future. */
-    private Handler mHandler;
+    private final Handler mHandler;
 
     /** The maximum number of fingers seen in the gesture. */
     private int mPointerCount = 0;
@@ -81,9 +81,10 @@ public class TapGestureDetector {
         public void handleMessage(Message message) {
             TapGestureDetector detector = mDetector.get();
             if (detector != null) {
+                detector.mTapCancelled = true;
                 detector.mListener.onLongPress(
                         detector.mPointerCount, detector.mInitialPoint.x, detector.mInitialPoint.y);
-                detector.mTapCancelled = true;
+                detector.mInitialPoint = null;
             }
         }
     }
@@ -102,9 +103,10 @@ public class TapGestureDetector {
         switch (event.getActionMasked()) {
             case MotionEvent.ACTION_DOWN:
                 reset();
+                trackDownEvent(event);
+
                 // Cause a long-press notification to be triggered after the timeout.
                 mHandler.sendEmptyMessageDelayed(0, ViewConfiguration.getLongPressTimeout());
-                trackDownEvent(event);
                 mPointerCount = 1;
                 break;