Avoid style clobbering in setCompositionFromExistingText. (2nd land)

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 296 matching lines @@
     // Always clear the x position used for vertical arrow navigation.
     // It will be restored by the vertical arrow navigation code if necessary.
     m_xPosForVerticalArrowNavigation = NoXPosForVerticalArrowNavigation();
     selectFrameElementInParentIfFullySelected();
     notifyLayoutObjectOfSelectionChange(userTriggered);
     // If the selections are same in the DOM tree but not in the composed tree,
     // don't fire events. For example, if the selection crosses shadow tree
     // boundary, selection for the DOM tree is shrunk while that for the
     // composed tree is not. Additionally, this case occurs in some edge cases.
     // See also: editing/pasteboard/4076267-3.html
-    if (VisibleSelection::InDOMTree::equalSelections(oldSelection, m_selection))
+    if (VisibleSelection::InDOMTree::equalSelections(oldSelection, m_selection)) {
+        m_frame->inputMethodController().cancelCompositionIfSelectionIsInvalid();
         return;
+    }
     m_frame->editor().respondToChangedSelection(oldSelection, options);
     if (userTriggered == UserTriggered) {
         ScrollAlignment alignment;
 
         if (m_frame->editor().behavior().shouldCenterAlignWhenSelectionIsRevealed())
             alignment = (align == AlignCursorOnScrollAlways) ? ScrollAlignment::alignCenterAlways : ScrollAlignment::alignCenterIfNeeded;
         else
             alignment = (align == AlignCursorOnScrollAlways) ? ScrollAlignment::alignTopAlways : ScrollAlignment::alignToEdgeIfNeeded;
 
         revealSelection(alignment, RevealExtent);
@@ skipping 1762 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil) FrameSelection.\n");
 }
 
 #endif