Keep the selection of the text field when changed by JS.

Source/core/editing/FrameSelection.cpp

Index: Source/core/editing/FrameSelection.cpp
diff --git a/Source/core/editing/FrameSelection.cpp b/Source/core/editing/FrameSelection.cpp
index 249dbe2971a8aef46f5b1312110060470eb50b9f..112b5dfcaefd9ba497eda47fd1761008d4a37a15 100644
--- a/Source/core/editing/FrameSelection.cpp
+++ b/Source/core/editing/FrameSelection.cpp
@@ -41,6 +41,7 @@
 #include "core/editing/GranularityStrategy.h"
 #include "core/editing/InputMethodController.h"
 #include "core/editing/RenderedPosition.h"
+#include "core/editing/SelectionController.h"
 #include "core/editing/SpellChecker.h"
 #include "core/editing/TypingCommand.h"
 #include "core/editing/VisibleUnits.h"
@@ -327,6 +328,7 @@ void FrameSelection::setSelection(const VisibleSelection& newSelection, SetSelec
 
     notifyAccessibilityForSelectionChange();
     notifyCompositorForSelectionChange();
+    notifyEventHandlerForSelectionChange();
     m_frame->localDOMWindow()->enqueueDocumentEvent(Event::create(EventTypeNames::selectionchange));
 }
 
@@ -1505,6 +1507,11 @@ void FrameSelection::notifyCompositorForSelectionChange()
     scheduleVisualUpdate();
 }
 
+void FrameSelection::notifyEventHandlerForSelectionChange()
+{
+    m_frame->eventHandler().selectionController().notifySelectionChanged();
+}
+
 void FrameSelection::focusedOrActiveStateChanged()
 {
     bool activeAndFocused = isFocusedAndActive();