[RenderText] added test for AppendText

ui/gfx/render_text.h

 // Copyright (c) 2012 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 UI_GFX_RENDER_TEXT_H_
 #define UI_GFX_RENDER_TEXT_H_
 
 #include <algorithm>
 #include <cstring>
 #include <string>
@@ skipping 600 matching lines @@
   // is within the given range.
   static bool RangeContainsCaret(const Range& range,
                                  size_t caret_pos,
                                  LogicalCursorDirection caret_affinity);
 
  private:
   friend class RenderTextTest;
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, DefaultStyles);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, SetStyles);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ApplyStyles);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, AppendTextKeepsStyles);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ObscuredText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, RevealObscuredText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ElidedText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ElidedObscuredText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, TruncatedText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, TruncatedObscuredText);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, GraphemePositions);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, MinLineHeight);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, EdgeSelectionModels);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, GetTextOffset);
@@ skipping 168 matching lines @@
   // Lines computed by EnsureLayout. These should be invalidated upon
   // OnLayoutTextAttributeChanged and OnDisplayTextAttributeChanged calls.
   std::vector<internal::Line> lines_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_