Add a UMA counter for tap disambiguation result.

content/public/android/java/src/org/chromium/content/browser/PopupZoomer.java

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
@@ skipping 12 matching lines @@
 import android.graphics.drawable.Drawable;
 import android.os.SystemClock;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.animation.Interpolator;
 import android.view.animation.OvershootInterpolator;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.Log;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.content.R;
 
 /**
- * PopupZoomer is used to show the on-demand link zooming popup. It handles manipulation of the
- * canvas and touch events to display the on-demand zoom magnifier.
+ * PopupZoomer is used to show the tap disambiguation popup.  When a tap lands ambiguously
+ * between two tiny touch targets (usually links) on a desktop site viewed on a phone,
+ * a magnified view of the content is shown, the screen is grayed out and the user
+ * must re-tap the magnified content in order to clarify their intent.
  */
 class PopupZoomer extends View {
     private static final String TAG = "cr.PopupZoomer";
 
     // The padding between the edges of the view and the popup. Note that there is a mirror
     // constant in content/renderer/render_view_impl.cc which should be kept in sync if
     // this is changed.
     private static final int ZOOM_BOUNDS_MARGIN = 25;
     // Time it takes for the animation to finish in ms.
     private static final long ANIMATION_DURATION = 300;
 
+    // Note that these values should be cross-checked against
+    // tools/metrics/histograms/histograms.xml.  Values should only be appended,
+    // not changed or removed.
+    private static final String UMA_TAPDISAMBIGUATION = "Touchscreen.TapDisambiguation";
+    private static final int UMA_TAPDISAMBIGUATION_OTHER = 0;
+    private static final int UMA_TAPDISAMBIGUATION_BACKBUTTON = 1;
+    private static final int UMA_TAPDISAMBIGUATION_TAPPEDOUTSIDE = 2;
+    private static final int UMA_TAPDISAMBIGUATION_TAPPEDINSIDE = 3;
+    private static final int UMA_TAPDISAMBIGUATION_COUNT = 4;
+
+    private void recordHistogram(int value) {
+        RecordHistogram.recordEnumeratedHistogram(
+                UMA_TAPDISAMBIGUATION, value, UMA_TAPDISAMBIGUATION_COUNT);
+    }
+
     /**
      * Interface to be implemented to listen for touch events inside the zoomed area.
      * The MotionEvent coordinates correspond to original unzoomed view.
      */
     public static interface OnTapListener {
         public boolean onSingleTap(View v, MotionEvent event);
         public boolean onLongPress(View v, MotionEvent event);
     }
 
     private OnTapListener mOnTapListener;
@@ skipping 122 matching lines @@
         setFocusableInTouchMode(true);
 
         GestureDetector.SimpleOnGestureListener listener =
                 new GestureDetector.SimpleOnGestureListener() {
                     @Override
                     public boolean onScroll(MotionEvent e1, MotionEvent e2,
                             float distanceX, float distanceY) {
                         if (mAnimating) return true;
 
                         if (isTouchOutsideArea(e1.getX(), e1.getY())) {
-                            hide(true);
+                            tappedOutside();
                         } else {
                             scroll(distanceX, distanceY);
                         }
                         return true;
                     }
 
                     @Override
                     public boolean onSingleTapUp(MotionEvent e) {
                         return handleTapOrPress(e, false);
                     }
 
                     @Override
                     public void onLongPress(MotionEvent e) {
                         handleTapOrPress(e, true);
                     }
 
                     private boolean handleTapOrPress(MotionEvent e, boolean isLongPress) {
                         if (mAnimating) return true;
 
                         float x = e.getX();
                         float y = e.getY();
                         if (isTouchOutsideArea(x, y)) {
-                            // User clicked on area outside the popup.
-                            hide(true);
+                            tappedOutside();
                         } else if (mOnTapListener != null) {
                             PointF converted = convertTouchPoint(x, y);
                             MotionEvent event = MotionEvent.obtainNoHistory(e);
                             event.setLocation(converted.x, converted.y);
                             if (isLongPress) {
                                 mOnTapListener.onLongPress(PopupZoomer.this, event);
                             } else {
                                 mOnTapListener.onSingleTap(PopupZoomer.this, event);
                             }
-                            hide(true);
+                            tappedInside();
                         }
                         return true;
                     }
                 };
         mGestureDetector = new GestureDetector(context, listener);
     }
 
     /**
      * Sets the OnTapListener.
      */
@@ skipping 266 matching lines @@
      * Show the PopupZoomer view with given target bounds.
      */
     public void show(Rect rect) {
         if (mShowing || mZoomedBitmap == null) return;
 
         setTargetBounds(rect);
         startAnimation(true);
     }
 
     /**
-     * Hide the PopupZoomer view.
+     * Hide the PopupZoomer view because of some external event such as focus
+     * change, JS-originating scroll, etc.
      * @param animation true if hide with animation.
      */
     public void hide(boolean animation) {
         if (!mShowing) return;
+        recordHistogram(UMA_TAPDISAMBIGUATION_OTHER);
 
         if (animation) {
             startAnimation(false);
         } else {
             hideImmediately();
         }
     }
+    private void tappedInside() {
+        if (!mShowing) return;
+        recordHistogram(UMA_TAPDISAMBIGUATION_TAPPEDINSIDE);
+
+        startAnimation(false);
+    }
+
+    private void tappedOutside() {
+        if (!mShowing) return;
+        recordHistogram(UMA_TAPDISAMBIGUATION_TAPPEDOUTSIDE);
+
+        startAnimation(false);
+    }
+
+    public void backButtonPressed() {
+        if (!mShowing) return;
+        recordHistogram(UMA_TAPDISAMBIGUATION_BACKBUTTON);
+
+        startAnimation(false);
+    }
 
     /**
      * Converts the coordinates to a point on the original un-zoomed view.
      */
     private PointF convertTouchPoint(float x, float y) {
         x -= mShiftX;
         y -= mShiftY;
         x = mTouch.x + (x - mTouch.x - mPopupScrollX) / mScale;
         y = mTouch.y + (y - mTouch.y - mPopupScrollY) / mScale;
         return new PointF(x, y);
@@ skipping 21 matching lines @@
         }
 
         @Override
         public float getInterpolation(float input) {
             input = 1.0f - input;
             if (mInterpolator == null) return input;
             return mInterpolator.getInterpolation(input);
         }
     }
 }