Add verifyInputEvent api to InputDispatcher

Now InputDispatcher will be able to check whether a certain InputEvent
is legitimate.
Use the 'verifyInputEvent' api to determine if a given 'InputEvent'
actually came from InputDispatcher.

Bug: 134977432
Test: atest VerifiedKeyEventTest VerifiedMotionEventTest libinput_tests
inputflinger_tests
Change-Id: I8e7fa9bfa3c14b0b0d949fb5e28b43ff7583398f
diff --git a/libs/input/tests/Android.bp b/libs/input/tests/Android.bp
index c1c35e1..fb21d5e 100644
--- a/libs/input/tests/Android.bp
+++ b/libs/input/tests/Android.bp
@@ -10,12 +10,12 @@
         "LatencyStatistics_test.cpp",
         "TouchVideoFrame_test.cpp",
         "VelocityTracker_test.cpp",
+        "VerifiedInputEvent_test.cpp",
     ],
     cflags: [
         "-Wall",
         "-Wextra",
         "-Werror",
-        "-Wno-unused-variable",
     ],
     shared_libs: [
         "libinput",