Only log dropped input when disabled for the first event.

Bug: 19851495
Change-Id: I8cb8076723c1ca1732c3bc37f283d8eb48b7bee0
diff --git a/services/inputflinger/InputDispatcher.h b/services/inputflinger/InputDispatcher.h
index 9a340c9..80eed56 100644
--- a/services/inputflinger/InputDispatcher.h
+++ b/services/inputflinger/InputDispatcher.h
@@ -857,6 +857,8 @@
     Queue<EventEntry> mRecentQueue;
     Queue<CommandEntry> mCommandQueue;
 
+    DropReason mLastDropReason;
+
     void dispatchOnceInnerLocked(nsecs_t* nextWakeupTime);
 
     // Enqueues an inbound event.  Returns true if mLooper->wake() should be called.