Merge "Remove IME surface when window unbinds" into rvc-dev

core/java/android/inputmethodservice/InputMethodService.java

@@ -611,6 +611,10 @@ public class InputMethodService extends AbstractInputMethodService {
         public void unbindInput() {
             if (DEBUG) Log.v(TAG, "unbindInput(): binding=" + mInputBinding
                     + " ic=" + mInputConnection);
+            // Unbind input is per process per display.
+            // TODO(b/150902448): free-up IME surface when target is changing.
+            //  e.g. DisplayContent#setInputMethodTarget()
+            removeImeSurface();
             onUnbindInput();
             mInputBinding = null;
             mInputConnection = null;