[LayoutNG] Fix whitespace collapsing when a node is a newline

third_party/WebKit/Source/core/layout/ng/ng_layout_inline_items_builder.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NGLayoutInlineItemsBuilder_h
 #define NGLayoutInlineItemsBuilder_h
 
 #include "core/CoreExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/Vector.h"
@@ skipping 43 matching lines @@
   void Append(const String&, const ComputedStyle*, LayoutObject* = nullptr);
 
   // Append a character.
   // Currently this function is for adding control characters such as
   // objectReplacementCharacter, and does not support all space collapsing logic
   // as its String version does.
   // See the String version for using nullptr for ComputedStyle and
   // LayoutObject.
   void Append(UChar, const ComputedStyle* = nullptr, LayoutObject* = nullptr);
 
-  // Append a character.
-  // The character is opaque to space collapsing that spaces before this
-  // character and after this character can collapse as if this character does
-  // not exist.
-  void AppendAsOpaqueToSpaceCollapsing(UChar);
+  // Append a Bidi control character, for LTR or RTL depends on the style.
   void AppendBidiControl(const ComputedStyle*, UChar ltr, UChar rtl);
 
   void EnterBlock(const ComputedStyle*);
   void ExitBlock();
   void EnterInline(LayoutObject*);
   void ExitInline(LayoutObject*);
 
  private:
   Vector<NGLayoutInlineItem>* items_;
   StringBuilder text_;
 
   typedef struct OnExitNode {
     LayoutObject* node;
     UChar character;
   } OnExitNode;
   Vector<OnExitNode> exits_;
 
-  bool is_last_collapsible_space_ = true;
-  bool has_pending_newline_ = false;
+  enum class CollapsibleSpace { None, Space, Newline };
+
+  CollapsibleSpace last_collapsible_space_ = CollapsibleSpace::Space;
   bool is_svgtext_ = false;
   bool has_bidi_controls_ = false;
 
   // Because newlines may be removed depends on following characters, newlines
   // at the end of input string is not added to |text_| but instead
   // |has_pending_newline_| flag is set.
   // This function determines whether to add the newline or ignore.
   void ProcessPendingNewline(const String&, const ComputedStyle*);
 
   // Removes the collapsible space at the end of |text_| if exists.
+  void RemoveTrailingCollapsibleSpaceIfExists(unsigned*);
   void RemoveTrailingCollapsibleSpace(unsigned*);
 
+  void RemoveTrailingCollapsibleNewlineIfNeeded(unsigned*,
+                                                const String&,
+                                                unsigned,
+                                                const ComputedStyle*);
+
   void Enter(LayoutObject*, UChar);
   void Exit(LayoutObject*);
 };
 
 }  // namespace blink
 
 #endif  // NGLayoutInlineItemsBuilder_h