Remove TidyUpHTMLStructure() from Editor.h

Editor::TidyUpHTMLStructure() is moved to EditingCommandsUtilities in
crrev.com/c/908388 miss removing the declaration in Editor.h, remove it.

Bug: 672405
Signed-off-by: Zhuoyu Qian <zhuoyu.qian@samsung.com>
Change-Id: I6c5276ba93d0e45e0cdd82b42b9d1aebbdb6a1c0
Reviewed-on: https://chromium-review.googlesource.com/933666
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539078}

third_party/WebKit/Source/core/editing/Editor.h

@@ -276,8 +276,6 @@ class CORE_EXPORT Editor final : public GarbageCollectedFinalized<Editor> {
     default_paragraph_separator_ = separator;
   }
 
-  static void TidyUpHTMLStructure(Document&);
-
   EditingStyle* TypingStyle() const;
   void SetTypingStyle(EditingStyle*);
   void ClearTypingStyle();