Refactor FrameSelection::RevealSelection

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 946 matching lines @@
 // TODO(editing-dev): This should be done in FlatTree world.
 void FrameSelection::RevealSelection(const ScrollAlignment& alignment,
                                      RevealExtentOption reveal_extent_option) {
   DCHECK(IsAvailable());
 
   // TODO(editing-dev): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   // Calculation of absolute caret bounds requires clean layout.
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
 
+  const VisibleSelection& selection = ComputeVisibleSelectionInDOMTree();
+  const Position& start = selection.Start();
+  DCHECK(start.AnchorNode());
+  if (!start.AnchorNode() || !start.AnchorNode()->GetLayoutObject())
+    return;
+
   LayoutRect rect;

[yosin_UTC9, 2017/07/07 05:12:51]

Let's move this switch-statement into a function in another patch.
Or if you want it is OK to move to function this patch.

-
-  switch (ComputeVisibleSelectionInDOMTree().GetSelectionType()) {
+  switch (selection.GetSelectionType()) {
     case kNoSelection:
       return;
     case kCaretSelection:
       rect = LayoutRect(AbsoluteCaretBounds());
       break;
-    case kRangeSelection:
+    case kRangeSelection: {
       rect = LayoutRect(
           reveal_extent_option == kRevealExtent
-              ? AbsoluteCaretBoundsOf(CreateVisiblePosition(
-                    ComputeVisibleSelectionInDOMTree().Extent()))
+              ? AbsoluteCaretBoundsOf(CreateVisiblePosition(selection.Extent()))
               : AbsoluteSelectionBoundsOf(ComputeVisibleSelectionInFlatTree()));
       break;
+    }
   }
 
-  Position start = ComputeVisibleSelectionInDOMTree().Start();
-  DCHECK(start.AnchorNode());
-  if (start.AnchorNode() && start.AnchorNode()->GetLayoutObject()) {
-    // FIXME: This code only handles scrolling the startContainer's layer, but
-    // the selection rect could intersect more than just that.
-    if (DocumentLoader* document_loader = frame_->Loader().GetDocumentLoader())
-      document_loader->GetInitialScrollState().was_scrolled_by_user = true;
-    if (start.AnchorNode()->GetLayoutObject()->ScrollRectToVisible(
-            rect, alignment, alignment))
-      UpdateAppearance();
-  }
+  // FIXME: This code only handles scrolling the startContainer's layer, but
+  // the selection rect could intersect more than just that.
+  if (DocumentLoader* document_loader = frame_->Loader().GetDocumentLoader())
+    document_loader->GetInitialScrollState().was_scrolled_by_user = true;
+  if (!start.AnchorNode()->GetLayoutObject()->ScrollRectToVisible(
+          rect, alignment, alignment))
+    return;
+
+  UpdateAppearance();
 }
 
 void FrameSelection::SetSelectionFromNone() {
   // Put a caret inside the body if the entire frame is editable (either the
   // entire WebView is editable or designMode is on for this document).
 
   Document* document = frame_->GetDocument();
   if (!ComputeVisibleSelectionInDOMTreeDeprecated().IsNone() ||
       !(blink::HasEditableStyle(*document)))
     return;
@@ skipping 177 matching lines @@
 }
 
 void showTree(const blink::FrameSelection* sel) {
   if (sel)
     sel->ShowTreeForThis();
   else
     LOG(INFO) << "Cannot showTree for <null> FrameSelection.";
 }
 
 #endif