Merge "Improve error message in WMS#isInTouchMode" into udc-dev am: a69c3fe77a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22913696

Change-Id: Id5bf16cd74ede1b2ad9f8ee73beb573fdee9feca
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

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

@@ -3915,8 +3915,9 @@ public class WindowManagerService extends IWindowManager.Stub
         synchronized (mGlobalLock) {
             final DisplayContent displayContent = mRoot.getDisplayContent(displayId);
             if (displayContent == null) {
-                throw new IllegalStateException("No touch mode is defined for displayId {"
-                        + displayId + "}");
+                throw new IllegalStateException("Failed to retrieve the touch mode state for"
+                        + "display {" + displayId + "}: display is not registered in "
+                        + "WindowRootContainer");
             }
             return displayContent.isInTouchMode();
         }