Make Editor.SuggestionsPopupWindow private again

Editor.SuggestionsPopupWindow was originally introduced as a private
class [1], then we made it public [2] so that a test class can access
it, but that test was later updated [3] and now doesn't have any
direct dependency on Editor.SuggestionsPopupWindow.

In short, we can make Editor.SuggestionsPopupWindow a private class
again without losing anything.  This actually addresses the following
warning from doclava.

   Public class android.widget.Editor.SuggestionsPopupWindow
   extends private class android.widget.Editor.PinnedPopupWindow

There should be no behavior change.

 [1]: If863107681ce82a1639f21315878f830c2991fb7
      6934044fd7
 [2]: Idf166cbecb3e33be213e4104cf1afd827906f2ad
      a60160b30b
 [3]: I12e522436a83fa264cd22176d054877eec411708
      31eb74fb2b

Fix: 117519592
Test: No doclava warning regarding SuggestionsPopupWindow during full build
Change-Id: Ie722156d3819d05d3cd479527abb8b4750b332f7

core/java/android/widget/Editor.java

@@ -3531,8 +3531,8 @@ public class Editor {
         }
     }
 
-    @VisibleForTesting
-    public class SuggestionsPopupWindow extends PinnedPopupWindow implements OnItemClickListener {
+    private final class SuggestionsPopupWindow extends PinnedPopupWindow
+            implements OnItemClickListener {
         private static final int MAX_NUMBER_SUGGESTIONS = SuggestionSpan.SUGGESTIONS_MAX_SIZE;
 
         // Key of intent extras for inserting new word into user dictionary.
@@ -3734,11 +3734,6 @@ public class Editor {
             }
         }
 
-        @VisibleForTesting
-        public ViewGroup getContentViewForTesting() {
-            return mContentView;
-        }
-
         @Override
         public void show() {
             if (!(mTextView.getText() instanceof Editable)) return;
@@ -6460,11 +6455,6 @@ public class Editor {
         return 0 <= start && start <= end && end <= text.length();
     }
 
-    @VisibleForTesting
-    public SuggestionsPopupWindow getSuggestionsPopupWindowForTesting() {
-        return mSuggestionsPopupWindow;
-    }
-
     /**
      * An InputFilter that monitors text input to maintain undo history. It does not modify the
      * text being typed (and hence always returns null from the filter() method).