Added UMA stat for tracking accidental navigations on double tap.

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

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index 026f9b45308f48da1e0c1f50d99e942cc844f698..5ba29e8d17ad8c2673c8b382b8665e4f1592db77 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -459,6 +459,19 @@ public class ContentViewCore
 
     private ViewAndroid mViewAndroid;
 
+    public static class UMAUserAction {

[Rick Byers, 2013/11/01 14:45:09]

Can't you use a Java enum type here?  Looks like we do elsewhere.

[bokan, 2013/11/01 18:52:44]

Changed.

+        // Enum for "action after double tap" UMA stat.
+        // Be sure to update histograms.xml if you update these.
+        public static final int NAVIGATE_BACK = 0;
+        public static final int NAVIGATE_STOP = 1;
+        public static final int NO_ACTION = 2;
+        public static final int ACTION_AFTER_DOUBLE_TAP_UMA_COUNT = 3;
+
+        // Not passed to UMA stats - used internally only

[Rick Byers, 2013/11/01 14:45:09]

Seems kind of hacky to include these in the enum...

[bokan, 2013/11/01 18:52:44]

I cleaned it up. PTAL

+        public static final int DOUBLE_TAP = 100;
+        public static final int DELAYED_TAP = 101;
+    }
+
 
     /**
      * Constructs a new ContentViewCore. Embedders must call initialize() after constructing
@@ -1323,6 +1336,10 @@ public class ContentViewCore
         }
     }
 
+    public void reportActionForUMA(int actionType) {
+        mContentViewGestureHandler.reportActionForUMA(actionType);
+    }
+
     @Override
     public boolean sendGesture(int type, long timeMs, int x, int y, Bundle b) {
         if (offerGestureToEmbedder(type)) return false;
@@ -1394,6 +1411,23 @@ public class ContentViewCore
     }
 
     @Override
+    public void sendUserActionUMA(int actionType, boolean clickDelayEnabled) {

[Rick Byers, 2013/11/01 14:45:09]

Is it not possible/easy to call into native directly form ContentGestureHandler?
 I didn't realize we'd have to call back into this class like this - sorry...

[bokan, 2013/11/01 18:52:44]

I don't think it has a binding class, there's an interface (MotionEventDelegate)
in GestureHandler this class implements that has a comment saying that's how
GestureHandler calls into native. I just added this method to that interface. 

+        int doubleTapEnumCount =
+                UMAUserAction.ACTION_AFTER_DOUBLE_TAP_UMA_COUNT;
+
+        if (actionType < doubleTapEnumCount) {
+            nativeSendActionAfterDoubleTapUma(
+                    mNativeContentViewCore,
+                    actionType,
+                    clickDelayEnabled,
+                    doubleTapEnumCount);
+        } else if (actionType
+                == UMAUserAction.DELAYED_TAP) {
+            nativeSendDelayedTapUma(mNativeContentViewCore);
+        }
+    }
+
+    @Override
     public void onSentLastGestureForVSync(long eventTimeMs) {
         if (isVSyncNotificationEnabled()) {
             mDidSignalVSyncUsingInputEvent = true;
@@ -3368,4 +3402,9 @@ public class ContentViewCore
 
     private native void nativeSetAccessibilityEnabled(
             int nativeContentViewCoreImpl, boolean enabled);
+
+    private native void nativeSendDelayedTapUma(int nativeContentViewCoreImpl);
+
+    private native void nativeSendActionAfterDoubleTapUma(int nativeContentViewCoreImpl,
+            int type, boolean hasDelay, int count);
 }