Remove hideCurrentInputMethod from RecentsAnimationController

Since CL[1] migrate hide IME logic when quick switching split-screen
task to InputMonitor.

As a result, remove unused API since it would be no longer to
expose hideCurrentInputMethod for launcher to handle gesture.

[1]: Ibfcd48e623336c4690b71c4db0ce1ad8f5b26fc9

Bug: 166736352
Bug: 193990612

Test: manual test as steps
1) launch any apps with focusing an editor
2) from overview, select any app to enter split-screen mode
3) taping the editor to show the keyboard
4) swipe up to overview or quick switch app tasks
5) expect the keyboard will be hidden when starting the gesture.

Change-Id: I299c3ac8531fa28c68c997e44fb168819e85d465

core/java/android/view/IRecentsAnimationController.aidl

@@ -79,11 +79,6 @@ interface IRecentsAnimationController {
     @UnsupportedAppUsage
     void setAnimationTargetsBehindSystemBars(boolean behindSystemBars);
 
-    /**
-     * Hides the current input method if one is showing.
-     */
-    void hideCurrentInputMethod();
-
     /**
      * Clean up the screenshot of previous task which was created during recents animation that
      * was cancelled by a stack order change.

packages/SystemUI/shared/src/com/android/systemui/shared/system/RecentsAnimationControllerCompat.java

@@ -65,14 +65,6 @@ public class RecentsAnimationControllerCompat {
         }
     }
 
-    public void hideCurrentInputMethod() {
-        try {
-            mAnimationController.hideCurrentInputMethod();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Failed to set hide input method", e);
-        }
-    }
-
     /**
      * Sets the final surface transaction on a Task. This is used by Launcher to notify the system
      * that animating Activity to PiP has completed and the associated task surface should be

packages/SystemUI/shared/src/com/android/systemui/shared/system/RemoteTransitionCompat.java

@@ -369,10 +369,6 @@ public class RemoteTransitionCompat implements Parcelable {
             if (mWrapped != null) mWrapped.setAnimationTargetsBehindSystemBars(behindSystemBars);
         }
 
-        @Override public void hideCurrentInputMethod() {
-            mWrapped.hideCurrentInputMethod();
-        }
-
         @Override public void setFinishTaskTransaction(int taskId,
                 PictureInPictureSurfaceTransaction finishTransaction, SurfaceControl overlay) {
             mPipTransaction = finishTransaction;

services/core/java/com/android/server/wm/RecentsAnimationController.java

@@ -352,10 +352,6 @@ public class RecentsAnimationController implements DeathRecipient {
             }
         }
 
-        // TODO(b/166736352): Remove this method without the need to expose to launcher.
-        @Override
-        public void hideCurrentInputMethod() { }
-
         @Override
         public void setDeferCancelUntilNextTransition(boolean defer, boolean screenshot) {
             synchronized (mService.mGlobalLock) {