First crack at implementing the touch explaration mode.

ui/events/gestures/gesture_sequence.cc

Index: ui/events/gestures/gesture_sequence.cc
diff --git a/ui/events/gestures/gesture_sequence.cc b/ui/events/gestures/gesture_sequence.cc
index 2ca15791c9fe3af74c26289ad73e50b30fb068da..b28f2fc6cbd755049da7524541d28069f0531879 100644
--- a/ui/events/gestures/gesture_sequence.cc
+++ b/ui/events/gestures/gesture_sequence.cc
@@ -512,6 +512,7 @@ GestureSequence::Gestures* GestureSequence::ProcessTouchEventForGesture(
   if (result & ER_CONSUMED)
     return NULL;
 
+  LOG(ERROR) << "GS::ProcessTouchEventForGesture, type=" << event.type();
   // Set a limit on the number of simultaneous touches in a gesture.
   if (event.touch_id() >= kMaxGesturePoints)
     return NULL;