Notify Content Capture the selection was changed

The ContentCapture service is interested in the selection changes.
When the selection was changed, notifies a text changed event to
ContentCapture.

Bug: 184311217
Test: manual
 1.long press trigger selection, event is sent.
 2.drag selection indicators, send event after the drag is done.
Test: atest CtsContentCaptureServiceTestCases
Change-Id: Ie45f617b132bc240b6cf61ee7ebc3041275f1694

core/java/android/widget/SelectionActionModeHelper.java

@@ -565,6 +565,7 @@ public final class SelectionActionModeHelper {
          */
         public void onSmartSelection(SelectionResult result) {
             onClassifiedSelection(result);
+            mTextView.notifyContentCaptureTextChanged();
             mLogger.logSelectionModified(
                     result.mStart, result.mEnd, result.mClassification, result.mSelection);
         }
@@ -595,6 +596,7 @@ public final class SelectionActionModeHelper {
                 mSelectionStart = selectionStart;
                 mSelectionEnd = selectionEnd;
                 mAllowReset = false;
+                mTextView.notifyContentCaptureTextChanged();
                 mLogger.logSelectionModified(selectionStart, selectionEnd, classification, null);
             }
         }