Prevent infinite loop about itemizing text in RenderTextHarfBuzz.

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 "base/i18n/bidi_line_iterator.h"
 #include "base/i18n/break_iterator.h"
@@ skipping 1133 matching lines @@
     run_list_out->InitIndexMap();
     return;
   }
 
   // Temporarily apply composition underlines and selection colors.
   ApplyCompositionAndSelectionStyles();
 
   // Build the run list from the script items and ranged styles and baselines.
   // Use an empty color BreakList to avoid breaking runs at color boundaries.
   BreakList<SkColor> empty_colors;
-  empty_colors.SetMax(text.length());
+  // StyleIterator is specified over the text, which can be different from
+  // |text| variable given in the argument. Therefore its max should be
+  // the text length, not "text->length()", otherwise it prevents to reach
+  // to the end of the given text in the loop below.
+  empty_colors.SetMax(this->text().length());

[msw, 2015/03/24 01:56:31]

Just use colors().max() and remove this comment.

   internal::StyleIterator style(empty_colors, baselines(), styles());
 
   for (size_t run_break = 0; run_break < text.length();) {
     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);
@@ skipping 12 matching lines @@
         TextIndexToGivenTextIndex(text, style.GetRange().end()));
 
     // 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);
 
     DCHECK(IsValidCodePointIndex(text, run_break));
     style.UpdatePosition(DisplayIndexToTextIndex(run_break));

[msw, 2015/03/24 01:56:31]

ItemizeTextToRuns is called with the layout text and the display text as the
|text| argument at different times. The use of DisplayIndexToTextIndex will be
wrong in the case of layout text... Perhaps that's [part of] the defect?

     run->range.set_end(run_break);
 
     run_list_out->add(run);
   }
 
   // Undo the temporarily applied composition underlines and selection colors.
   UndoCompositionAndSelectionStyles();
 
   run_list_out->InitIndexMap();
 }
@@ skipping 317 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