Add explicit method to dismiss Keyguard

The flag is a bit clunky for most cases, and a method is more
clear.

Test: cts/hostsidetests/services/activityandwindowmanager/util/run-test
android.server.cts.KeyguardTests

Test: cts/hostsidetests/services/activityandwindowmanager/util/run-test
android.server.cts.KeyguardLockedTests

Test: runtest systemui -c
com.android.systemui.keyguard.DismissCallbackRegistryTest

Bug: 30961403
Bug: 27422134
Change-Id: I39de90c7cfecd99350a74f72cd76418e337f2b79
diff --git a/Android.mk b/Android.mk
index 552103d..78c9c1d 100644
--- a/Android.mk
+++ b/Android.mk
@@ -338,6 +338,7 @@
 	core/java/com/android/internal/backup/IObbBackupService.aidl \
 	core/java/com/android/internal/inputmethod/IInputContentUriToken.aidl \
 	core/java/com/android/internal/policy/IKeyguardDrawnCallback.aidl \
+	core/java/com/android/internal/policy/IKeyguardDismissCallback.aidl \
 	core/java/com/android/internal/policy/IKeyguardExitCallback.aidl \
 	core/java/com/android/internal/policy/IKeyguardService.aidl \
 	core/java/com/android/internal/policy/IKeyguardStateCallback.aidl \