Introduce HasVisibleFirstLetter() for CanBeBackwardCaretPosition()

third_party/WebKit/Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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
@@ skipping 1445 matching lines @@
       return false;
     if (LineLayoutAPIShim::LayoutObjectFrom(runner->GetLineLayoutItem()) ==
             text_layout_object &&
         ToInlineTextBox(runner)->Start() >= text_offset)
       return false;
   }
 
   return true;
 }
 
+// Returns true if |text_layout_object| has visible first-letter.
+bool IsVisibleFirstLetter(const LayoutText& text_layout_object) {

[yoichio, 2017/06/16 07:48:50]

Function name is "Has"VisibleFirstLetter ?

[yosin_UTC9, 2017/06/16 07:58:18]

Done.

+  if (!text_layout_object.IsTextFragment())
+    return false;
+  const LayoutTextFragment& layout_text_fragment =
+      ToLayoutTextFragment(text_layout_object);
+  if (!layout_text_fragment.IsRemainingTextLayoutObject())
+    return false;
+  const LayoutObject* first_letter_layout_object =
+      layout_text_fragment.GetFirstLetterPseudoElement()->GetLayoutObject();
+  if (!first_letter_layout_object)
+    return false;
+  return first_letter_layout_object->Style()->Visibility() ==
+         EVisibility::kVisible;
+}
+
 // TODO(editing-dev): This function is just moved out from
 // |MostBackwardCaretPosition()|. We should study this function more and
 // name it appropriately. See https://trac.webkit.org/changeset/32438/
 // which introduce this.
 static bool CanBeBackwardCaretPosition(const LayoutText* text_layout_object,
                                        int offset_in_node) {
   const unsigned text_start_offset = text_layout_object->TextStartOffset();
   DCHECK_GE(offset_in_node, static_cast<int>(text_start_offset));
   const unsigned text_offset = offset_in_node - text_start_offset;
   InlineTextBox* const last_text_box = text_layout_object->LastTextBox();
   for (InlineTextBox* box : InlineTextBoxesOf(*text_layout_object)) {
     if (text_offset == box->Start()) {
-      if (text_layout_object->IsTextFragment() &&
-          ToLayoutTextFragment(text_layout_object)
-              ->IsRemainingTextLayoutObject()) {
+      if (IsVisibleFirstLetter(*text_layout_object)) {
         // |offset_in_node| is at start of remaining text of
         // |Text| node with :first-letter.
         DCHECK_GE(offset_in_node, 1);
-        LayoutObject* first_letter_layout_object =
-            ToLayoutTextFragment(text_layout_object)
-                ->GetFirstLetterPseudoElement()
-                ->GetLayoutObject();
-        if (first_letter_layout_object &&
-            first_letter_layout_object->Style()->Visibility() ==
-                EVisibility::kVisible)
-          return true;
+        return true;
       }
       continue;
     }
     if (text_offset <= box->Start() + box->Len()) {
       if (text_offset > box->Start())
         return true;
       continue;
     }
 
     if (box == last_text_box || text_offset != box->Start() + box->Len() + 1)
@@ skipping 579 matching lines @@
 
 IntRect ComputeTextRect(const EphemeralRangeInFlatTree& range) {
   return EnclosingIntRect(ComputeTextRectTemplate(range));
 }
 
 FloatRect ComputeTextFloatRect(const EphemeralRange& range) {
   return ComputeTextRectTemplate(range);
 }
 
 }  // namespace blink