Add input device property for buttons under touchpads

Bug: 8990644
Change-Id: I6df5fb9e11199173d62523928082db428af55394
diff --git a/libs/input/InputDevice.cpp b/libs/input/InputDevice.cpp
index 77fa49d..54703d4 100644
--- a/libs/input/InputDevice.cpp
+++ b/libs/input/InputDevice.cpp
@@ -136,6 +136,7 @@
         mKeyboardType(other.mKeyboardType),
         mKeyCharacterMap(other.mKeyCharacterMap),
         mHasVibrator(other.mHasVibrator),
+        mHasButtonUnderPad(other.mHasButtonUnderPad),
         mMotionRanges(other.mMotionRanges) {
 }
 
@@ -152,6 +153,7 @@
     mSources = 0;
     mKeyboardType = AINPUT_KEYBOARD_TYPE_NONE;
     mHasVibrator = false;
+    mHasButtonUnderPad = false;
     mMotionRanges.clear();
 }