Make IME extract text fields public

InputMethodService uses the following IDs for extract view.
- R.id.inputExtractEditText
- R.id.inputExtractAction
- R.id.inputExtractAccessories
While the first one is public, others are not. It makes sense to make
all of the public so IMEs can customize it.

Bug: 210777608
Test: atest InputMethodServiceTest

Change-Id: I125767d67839293c0b0f40c750d0fb1bb77951e9

core/java/android/inputmethodservice/InputMethodService.java

@@ -2175,10 +2175,12 @@ public class InputMethodService extends AbstractInputMethodService {
     }
     
     /**
-     * Called by the framework to create the layout for showing extacted text.
+     * Called by the framework to create the layout for showing extracted text.
      * Only called when in fullscreen mode.  The returned view hierarchy must
      * have an {@link ExtractEditText} whose ID is 
-     * {@link android.R.id#inputExtractEditText}.
+     * {@link android.R.id#inputExtractEditText}, with action ID
+     * {@link android.R.id#inputExtractAction} and accessories ID
+     * {@link android.R.id#inputExtractAccessories}.
      */
     public View onCreateExtractTextView() {
         return mInflater.inflate(