Revert "Plumb IME subtype change from IMMS to IMS."

This reverts commit b097b8262ba22040d46d6e212a31b758b7023307 [1].

Reason for revert:
This is the part 3 of a series of reverts to unlaunch Bug 25752812,
which aimed to improve UX but did not work well.

Note that since this was just a plumbing CL, reverting this CL itself
should introduce no user-visible behavior change.

See I7a2ed6dd39dcd8207d3d94e12cd01d5d67ba4bb5 for the detailed reason
of revert.

 [1]: I58e71ffce9ac9131551a00dd35e24235dadfef87

Bug: 66498367
Test: Manually done
Change-Id: I3e2b9a9faf5234e53d20953886d9d55af680087d
diff --git a/services/core/java/com/android/server/input/InputManagerService.java b/services/core/java/com/android/server/input/InputManagerService.java
index a70909f..451acf4 100644
--- a/services/core/java/com/android/server/input/InputManagerService.java
+++ b/services/core/java/com/android/server/input/InputManagerService.java
@@ -17,7 +17,6 @@
 package com.android.server.input;
 
 import android.annotation.NonNull;
-import android.annotation.Nullable;
 import android.os.LocaleList;
 import android.os.ShellCallback;
 import android.util.Log;
@@ -96,8 +95,6 @@
 import android.view.PointerIcon;
 import android.view.Surface;
 import android.view.ViewConfiguration;
-import android.view.inputmethod.InputMethodInfo;
-import android.view.inputmethod.InputMethodSubtype;
 import android.widget.Toast;
 
 import java.io.File;
@@ -135,7 +132,6 @@
     private static final int MSG_UPDATE_KEYBOARD_LAYOUTS = 4;
     private static final int MSG_RELOAD_DEVICE_ALIASES = 5;
     private static final int MSG_DELIVER_TABLET_MODE_CHANGED = 6;
-    private static final int MSG_INPUT_METHOD_SUBTYPE_CHANGED = 7;
 
     // Pointer to native input manager service object.
     private final long mPtr;
@@ -1429,15 +1425,6 @@
         }
     }
 
-    // Must be called on handler.
-    private void handleSwitchInputMethodSubtype(int userId,
-            @Nullable InputMethodInfo inputMethodInfo, @Nullable InputMethodSubtype subtype) {
-        if (DEBUG) {
-            Slog.i(TAG, "InputMethodSubtype changed: userId=" + userId
-                    + " ime=" + inputMethodInfo + " subtype=" + subtype);
-        }
-    }
-
     public void switchKeyboardLayout(int deviceId, int direction) {
         mHandler.obtainMessage(MSG_SWITCH_KEYBOARD_LAYOUT, deviceId, direction).sendToTarget();
     }
@@ -2065,22 +2052,12 @@
                 case MSG_RELOAD_DEVICE_ALIASES:
                     reloadDeviceAliases();
                     break;
-                case MSG_DELIVER_TABLET_MODE_CHANGED: {
+                case MSG_DELIVER_TABLET_MODE_CHANGED:
                     SomeArgs args = (SomeArgs) msg.obj;
                     long whenNanos = (args.argi1 & 0xFFFFFFFFl) | ((long) args.argi2 << 32);
                     boolean inTabletMode = (boolean) args.arg1;
                     deliverTabletModeChanged(whenNanos, inTabletMode);
                     break;
-                }
-                case MSG_INPUT_METHOD_SUBTYPE_CHANGED: {
-                    final int userId = msg.arg1;
-                    final SomeArgs args = (SomeArgs) msg.obj;
-                    final InputMethodInfo inputMethodInfo = (InputMethodInfo) args.arg1;
-                    final InputMethodSubtype subtype = (InputMethodSubtype) args.arg2;
-                    args.recycle();
-                    handleSwitchInputMethodSubtype(userId, inputMethodInfo, subtype);
-                    break;
-                }
             }
         }
     }
@@ -2242,16 +2219,6 @@
         }
 
         @Override
-        public void onInputMethodSubtypeChanged(int userId,
-                @Nullable InputMethodInfo inputMethodInfo, @Nullable InputMethodSubtype subtype) {
-            final SomeArgs someArgs = SomeArgs.obtain();
-            someArgs.arg1 = inputMethodInfo;
-            someArgs.arg2 = subtype;
-            mHandler.obtainMessage(MSG_INPUT_METHOD_SUBTYPE_CHANGED, userId, 0, someArgs)
-                    .sendToTarget();
-        }
-
-        @Override
         public void toggleCapsLock(int deviceId) {
             nativeToggleCapsLock(mPtr, deviceId);
         }