Introduce @SoftInputModeFlags annotation

Doing this allows us to annotate integer values that should corresponds
to WindowManager.LayoutParams#softInputMode.

Test: There should be no behavior change.  RetentionPolicy.SOURCE
      annotation should change nothing in production code.
Test: checkbuild
Bug: 32784563
Bug: 35079353
Change-Id: I96300b090edce327d0515c740183abe91ded6bac
diff --git a/services/core/java/com/android/server/InputMethodManagerService.java b/services/core/java/com/android/server/InputMethodManagerService.java
index b2b8f85..fd7a27f 100644
--- a/services/core/java/com/android/server/InputMethodManagerService.java
+++ b/services/core/java/com/android/server/InputMethodManagerService.java
@@ -2278,7 +2278,8 @@
 
     private InputBindResult windowGainedFocus(
             /* @InputMethodClient.StartInputReason */ final int startInputReason,
-            IInputMethodClient client, IBinder windowToken, int controlFlags, int softInputMode,
+            IInputMethodClient client, IBinder windowToken, int controlFlags,
+            /* @android.view.WindowManager.LayoutParams.SoftInputModeFlags */ int softInputMode,
             int windowFlags, EditorInfo attribute, IInputContext inputContext,
             /* @InputConnectionInspector.missingMethods */  final int missingMethods) {
         // Needs to check the validity before clearing calling identity