Trim text from autofillvalue when checking for empty.

Test: VirtualContainerActivityTest#testSaveDialogNotShownWhenBackIsPressed
Fixes: 62667931

Change-Id: I7e673eedd39fff7af89c694d0bfc5a495f14ea26

core/java/android/view/autofill/AutofillValue.java

@@ -141,7 +141,10 @@ public final class AutofillValue implements Parcelable {
      * @hide
      */
     public boolean isEmpty() {
-        return isText() && ((CharSequence) mValue).length() == 0;
+        if (!isText()) return false;
+
+        final CharSequence text = (CharSequence) mValue;
+        return text == null || TextUtils.getTrimmedLength(text) == 0;
     }
 
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