Revert [MacViews] Implemented text context menu

ui/gfx/decorated_text_mac.mm

Index: ui/gfx/decorated_text_mac.mm
diff --git a/ui/gfx/decorated_text_mac.mm b/ui/gfx/decorated_text_mac.mm
deleted file mode 100644
index 3a6ae10524fbda9932f41ec01e8105c27b729cf8..0000000000000000000000000000000000000000
--- a/ui/gfx/decorated_text_mac.mm
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright 2017 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.
-
-#import "ui/gfx/decorated_text_mac.h"
-
-#import <Cocoa/Cocoa.h>
-
-#import "base/mac/scoped_nsobject.h"
-#include "base/strings/sys_string_conversions.h"
-#include "ui/gfx/decorated_text.h"
-
-namespace gfx {
-
-NSAttributedString* GetAttributedStringFromDecoratedText(
-    const DecoratedText& decorated_text) {
-  base::scoped_nsobject<NSMutableAttributedString> str(
-      [[NSMutableAttributedString alloc]
-          initWithString:base::SysUTF16ToNSString(decorated_text.text)]);
-  [str beginEditing];
-
-  NSValue* const line_style =
-      @(NSUnderlineStyleSingle | NSUnderlinePatternSolid);
-
-  for (const auto& attribute : decorated_text.attributes) {
-    DCHECK(!attribute.range.is_reversed());
-    DCHECK_LE(attribute.range.end(), [str length]);
-
-    NSMutableDictionary* attrs = [NSMutableDictionary dictionary];
-    NSRange range = attribute.range.ToNSRange();
-
-    if (attribute.font.GetNativeFont())
-      attrs[NSFontAttributeName] = attribute.font.GetNativeFont();
-
-    // NSFont does not have underline as an attribute. Hence handle it
-    // separately.
-    const bool underline = attribute.font.GetStyle() & gfx::Font::UNDERLINE;
-    if (underline)
-      attrs[NSUnderlineStyleAttributeName] = line_style;
-
-    if (attribute.strike)
-      attrs[NSStrikethroughStyleAttributeName] = line_style;
-
-    [str setAttributes:attrs range:range];
-  }
-
-  [str endEditing];
-  return str.autorelease();
-}
-
-}  // namespace gfx