Added UMA stat for tracking accidental navigations on double tap.

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

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
index a680c9823e2a5198f97fca9f9ba0447bd16c0985..29631b4920005883cc8a45fdd298900902f91081 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
@@ -337,6 +337,18 @@ class ContentViewGestureHandler implements LongPressDelegate {
          * Show the zoom picker UI.
          */
         public void invokeZoomPicker();
+
+        /**
+         * Send action after dobule tap for UMA stat tracking

[Rick Byers, 2013/11/01 19:27:03]

nit - missing period here and below.

[Rick Byers, 2013/11/01 19:27:03]

nit - Looks like convention is to add javadoc comments for parameters, please
add here and below.

[bokan, 2013/11/01 19:54:02]

Done.

[bokan, 2013/11/01 19:54:02]

Done.

+         */
+        public void sendActionAfterDoubleTapUMA(
+                ContentViewCore.UMAActionAfterDoubleTap type,
+                boolean clickDelayEnabled);
+
+        /**
+         * Send single tap UMA
+         */
+        public void sendSingleTapUMA(ContentViewCore.UMASingleTapType type);
     }
 
     ContentViewGestureHandler(
@@ -532,6 +544,13 @@ class ContentViewGestureHandler implements LongPressDelegate {
                         // These corner cases should be ignored.
                         if (mLongPressDetector.isInLongPress() || mIgnoreSingleTap) return true;
 
+                        if (!isDoubleTapDisabled() && !mDisableClickDelay)
+                            mMotionEventDelegate.sendSingleTapUMA(

[Rick Byers, 2013/11/01 19:27:03]

nit - don't repeat the call to the function, just make the parameter be
conditional (inline or with a local variable).  Eg:
isDoubleTapDisabled || mDisableClickDelay ? UNDELAYED_TAP : DELAYED_TAP;

[bokan, 2013/11/01 19:54:02]

Done.

+                                    ContentViewCore.UMASingleTapType.DELAYED_TAP);
+                        else
+                            mMotionEventDelegate.sendSingleTapUMA(
+                                    ContentViewCore.UMASingleTapType.UNDELAYED_TAP);
+
                         int x = (int) e.getX();
                         int y = (int) e.getY();
                         mExtraParamBundleSingleTap.putBoolean(SHOW_PRESS, mShowPressIsCalled);
@@ -1137,12 +1156,17 @@ class ContentViewGestureHandler implements LongPressDelegate {
 
     private boolean sendMotionEventAsGesture(
             int type, MotionEvent event, Bundle extraParams) {
-        return mMotionEventDelegate.sendGesture(type, event.getEventTime(),
+        return sendGesture(type, event.getEventTime(),
             (int) event.getX(), (int) event.getY(), extraParams);
     }
 
     private boolean sendGesture(
             int type, long timeMs, int x, int y, Bundle extraParams) {
+        updateDoubleTapUmaTimer();
+
+        if (type == GESTURE_DOUBLE_TAP)
+            reportDoubleTap();
+
         return mMotionEventDelegate.sendGesture(type, timeMs, x, y, extraParams);
     }
 
@@ -1151,7 +1175,7 @@ class ContentViewGestureHandler implements LongPressDelegate {
         // VSync should only be signalled if the sent gesture was generated from a touch event.
         mSentGestureNeedsVSync = mInputEventsDeliveredAtVSync && mTouchEventHandlingStackDepth > 0;
         mLastVSyncGestureTimeMs = timeMs;
-        return mMotionEventDelegate.sendGesture(type, timeMs, x, y, extraParams);
+        return sendGesture(type, timeMs, x, y, extraParams);
     }
 
     void sendShowPressCancelIfNecessary(MotionEvent e) {
@@ -1267,4 +1291,53 @@ class ContentViewGestureHandler implements LongPressDelegate {
         }
 
     }
+
+    public void reportDoubleTap() {
+        // Make sure repeated double taps don't get silently dropped from
+        // the statistics.
+        if (mLastDoubleTapTimeMs > 0)
+            mMotionEventDelegate.sendActionAfterDoubleTapUMA(
+                    ContentViewCore.UMAActionAfterDoubleTap.NO_ACTION,
+                    !mDisableClickDelay);
+
+        mLastDoubleTapTimeMs = SystemClock.uptimeMillis();
+    }
+
+    public void reportActionAfterDoubleTapUMA(
+            ContentViewCore.UMAActionAfterDoubleTap type) {
+        updateDoubleTapUmaTimer();
+
+        if (mLastDoubleTapTimeMs == 0)
+            return;
+
+        long nowMs = SystemClock.uptimeMillis();
+        if ((nowMs - mLastDoubleTapTimeMs)
+                < ACTION_AFTER_DOUBLE_TAP_WINDOW_MS) {
+            mMotionEventDelegate.sendActionAfterDoubleTapUMA(
+                    type, !mDisableClickDelay);
+            mLastDoubleTapTimeMs = 0;
+        }
+    }
+
+    // Watch for the UMA "action after double tap" timer expiring and reset
+    // the timer if necessary.
+    private void updateDoubleTapUmaTimer() {
+        if (mLastDoubleTapTimeMs == 0)
+            return;
+
+        long nowMs = SystemClock.uptimeMillis();
+        if ((nowMs - mLastDoubleTapTimeMs)
+              >= ACTION_AFTER_DOUBLE_TAP_WINDOW_MS) {
+            // Time expired, user took no action (that we care about).
+            mMotionEventDelegate.sendActionAfterDoubleTapUMA(
+                    ContentViewCore.UMAActionAfterDoubleTap.NO_ACTION,
+                    !mDisableClickDelay);
+            mLastDoubleTapTimeMs = 0;
+        }
+    }
+
+    // Used for tracking UMA ActionAfterDoubleTap to tell user's immediate
+    // action after a double tap.
+    private long mLastDoubleTapTimeMs = 0;
+    private static final long ACTION_AFTER_DOUBLE_TAP_WINDOW_MS = 5000;
 }