Add HIDE_REMOVE_CLIENT into InputMethodDebug

CL [1] introduced the HIDE_REMOVE_CLIENT reason in
SoftInputShowHideReason.

Add this reason into InputMethodDebug to avoid dump
unknown reason unexpectedly.

[1]: Ifb91111f7136952462678ff6d0a5e917abb5005e

Bug: 167780081
Test: atest InputMethodDebugTest
Change-Id: I23a8deea66600e3e31bdcb5fbf8fb87d91c57e4d

core/java/com/android/internal/inputmethod/InputMethodDebug.java

@@ -226,6 +226,8 @@ public final class InputMethodDebug {
                 return "HIDE_RECENTS_ANIMATION";
             case SoftInputShowHideReason.HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR:
                 return "HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR";
+            case SoftInputShowHideReason.HIDE_REMOVE_CLIENT:
+                return "HIDE_REMOVE_CLIENT";
             default:
                 return "Unknown=" + reason;
         }

core/tests/coretests/src/com/android/internal/inputmethod/InputMethodDebugTest.java

@@ -65,4 +65,12 @@ public class InputMethodDebugTest {
                 InputMethodDebug.startInputFlagsToString(
                         StartInputFlags.VIEW_HAS_FOCUS | StartInputFlags.INITIAL_CONNECTION));
     }
+
+    @Test
+    public void testSoftInputDisplayReasonToString() {
+        // TODO: add more tests
+        assertEquals("HIDE_REMOVE_CLIENT",
+                InputMethodDebug.softInputDisplayReasonToString(
+                        SoftInputShowHideReason.HIDE_REMOVE_CLIENT));
+    }
 }