Add more assertion to render_text_harfbuzz.

ui/gfx/render_text_harfbuzz.cc

 // Copyright 2014 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.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <set>
 
 #include "base/i18n/bidi_line_iterator.h"
@@ skipping 1248 matching lines @@
     internal::TextRunHarfBuzz* run = new internal::TextRunHarfBuzz;
     run->range.set_start(run_break);
     run->font_style = (style.style(BOLD) ? Font::BOLD : 0) |
                       (style.style(ITALIC) ? Font::ITALIC : 0);
     run->baseline_type = style.baseline();
     run->strike = style.style(STRIKE);
     run->diagonal_strike = style.style(DIAGONAL_STRIKE);
     run->underline = style.style(UNDERLINE);
     int32 script_item_break = 0;
     bidi_iterator.GetLogicalRun(run_break, &script_item_break, &run->level);
+    CHECK_GT(static_cast<size_t>(script_item_break), run_break);
     // Odd BiDi embedding levels correspond to RTL runs.
     run->is_rtl = (run->level % 2) == 1;
     // Find the length and script of this script run.
     script_item_break = ScriptInterval(text, run_break,
         script_item_break - run_break, &run->script) + run_break;
 
     // Find the next break and advance the iterators as needed.
     const size_t new_run_break = std::min(
         static_cast<size_t>(script_item_break),
         TextIndexToGivenTextIndex(text, style.GetRange().end()));
-    CHECK_NE(new_run_break, run_break)
+    CHECK_GT(new_run_break, run_break)
         << "It must proceed! " << text << " " << run_break;
     run_break = new_run_break;
 
     // Break runs at certain characters that need to be rendered separately to
     // prevent either an unusual character from forcing a fallback font on the
     // entire run, or brackets from being affected by a fallback font.
     // http://crbug.com/278913, http://crbug.com/396776
     if (run_break > run->range.start())
       run_break = FindRunBreakingCharacter(text, run->range.start(), run_break);
 
@@ skipping 268 matching lines @@
   DCHECK(!update_layout_run_list_);
   DCHECK(!update_display_run_list_);
   return text_elided() ? display_run_list_.get() : &layout_run_list_;
 }
 
 const internal::TextRunList* RenderTextHarfBuzz::GetRunList() const {
   return const_cast<RenderTextHarfBuzz*>(this)->GetRunList();
 }
 
 }  // namespace gfx