[Android] Reland "Provide unhandled tap event notifications"

content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java

Index: content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java
diff --git a/content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java b/content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java
index 8cb82d6b9c130270fcb023648fea2a7536d12aaa..15971606a1eb10542b1ff3389e6978dd6e8760b2 100644
--- a/content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java
+++ b/content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.java
@@ -61,4 +61,9 @@ public class GestureStateListener {
      * Called when the scroll offsets or extents may have changed.
      */
     public void onScrollOffsetOrExtentChanged(int scrollOffsetY, int scrollExtentY) {}
+
+    /*
+     * Called when a tap event was not handled by the renderer.
+     */
+    public void onUnhandledTapEvent(int x, int y) {}
 }