Get rid of redundant layout tree update related to selection

third_party/WebKit/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 212 matching lines @@
   if (shouldClearTypingStyle)
     m_frame->editor().clearTypingStyle();
 
   const SelectionInDOMTree oldSelectionInDOMTree =
       m_selectionEditor->selectionInDOMTree();
   if (oldSelectionInDOMTree == newSelection)
     return;
   m_selectionEditor->setSelection(newSelection);
   scheduleVisualUpdateForPaintInvalidationIfNeeded();
 
-  // TODO(yosin): The use of updateStyleAndLayoutIgnorePendingStylesheets
-  // needs to be audited. see http://crbug.com/590369 for more details.
-  document().updateStyleAndLayoutIgnorePendingStylesheets();
-
   const Document& currentDocument = document();
   // TODO(yosin): We should get rid of unsued |options| for
   // |Editor::respondToChangedSelection()|.
   // Note: Since, setting focus can modify DOM tree, we should use
   // |oldSelection| before setting focus
   m_frame->editor().respondToChangedSelection(
-      createVisibleSelection(oldSelectionInDOMTree).start(), options);
+      oldSelectionInDOMTree.computeStartPosition(), options);
   DCHECK_EQ(currentDocument, document());
 
-  if (!computeVisibleSelectionInDOMTree().isNone() &&
-      !(options & DoNotSetFocus)) {
+  if (!selectionInDOMTree().isNone() && !(options & DoNotSetFocus)) {
     setFocusedNodeIfNeeded();
     // |setFocusedNodeIfNeeded()| dispatches sync events "FocusOut" and
     // "FocusIn", |m_frame| may associate to another document.
     if (!isAvailable() || document() != currentDocument) {
       // Once we get test case to reach here, we should change this
       // if-statement to |DCHECK()|.
       NOTREACHED();
       return;
     }
   }
@@ skipping 521 matching lines @@
   // Find the parent frame; if there is none, then we have nothing to do.
   Frame* parent = m_frame->tree().parent();
   if (!parent)
     return;
   Page* page = m_frame->page();
   if (!page)
     return;
 
   // Check if the selection contains the entire frame contents; if not, then
   // there is nothing to do.
-  if (!isRange())
+  if (selectionInDOMTree().selectionTypeWithLegacyGranularity() !=
+      RangeSelection) {
     return;
+  }
 
   // TODO(xiaochengh): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   document().updateStyleAndLayoutIgnorePendingStylesheets();
 
   if (!isStartOfDocument(selection().visibleStart()))
     return;
   if (!isEndOfDocument(selection().visibleEnd()))
     return;
 
@@ skipping 128 matching lines @@
   return m_selectionEditor->firstRange();
 }
 
 bool FrameSelection::isInPasswordField() const {
   TextControlElement* textControl = enclosingTextControl(start());
   return isHTMLInputElement(textControl) &&
          toHTMLInputElement(textControl)->type() == InputTypeNames::password;
 }
 
 void FrameSelection::notifyAccessibilityForSelectionChange() {
-  if (selection().start().isNotNull() && selection().end().isNotNull()) {
-    if (AXObjectCache* cache = document().existingAXObjectCache())
-      cache->selectionChanged(selection().start().computeContainerNode());
-  }
+  if (selectionInDOMTree().isNone())
+    return;
+  AXObjectCache* cache = document().existingAXObjectCache();
+  if (!cache)
+    return;
+  const Position& start = selectionInDOMTree().computeStartPosition();
+  cache->selectionChanged(start.computeContainerNode());
 }
 
 void FrameSelection::notifyCompositorForSelectionChange() {
   if (!RuntimeEnabledFeatures::compositedSelectionUpdateEnabled())
     return;
 
   scheduleVisualUpdate();
 }
 
 void FrameSelection::notifyEventHandlerForSelectionChange() {
@@ skipping 85 matching lines @@
 }
 
 void FrameSelection::updateAppearance() {
   DCHECK(!m_frame->contentLayoutItem().isNull());
   m_frameCaret->scheduleVisualUpdateForPaintInvalidationIfNeeded();
   m_pendingSelection->setHasPendingSelection();
 }
 
 void FrameSelection::notifyLayoutObjectOfSelectionChange(
     EUserTriggered userTriggered) {
-  if (TextControlElement* textControl = enclosingTextControl(start()))
-    textControl->selectionChanged(userTriggered == UserTriggered);
+  TextControlElement* textControl =
+      enclosingTextControl(selectionInDOMTree().base());
+  if (!textControl)
+    return;
+  textControl->selectionChanged(userTriggered == UserTriggered);
 }
 
 // Helper function that tells whether a particular node is an element that has
 // an entire LocalFrame and FrameView, a <frame>, <iframe>, or <object>.
 static bool isFrameElement(const Node* n) {
   if (!n)
     return false;
   LayoutObject* layoutObject = n->layoutObject();
   if (!layoutObject || !layoutObject->isLayoutPart())
     return false;
@@ skipping 347 matching lines @@
 }
 
 void showTree(const blink::FrameSelection* sel) {
   if (sel)
     sel->showTreeForThis();
   else
     LOG(INFO) << "Cannot showTree for <null> FrameSelection.";
 }
 
 #endif