Move unusual character block logic to a helper function

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 <map>
 
 #include "base/i18n/bidi_line_iterator.h"
 #include "base/i18n/break_iterator.h"
@@ skipping 259 matching lines @@
   hb_font_make_immutable(harfbuzz_font);
   return harfbuzz_font;
 }
 
 // Returns true if characters of |block_code| may trigger font fallback.
 bool IsUnusualBlockCode(UBlockCode block_code) {
   return block_code == UBLOCK_GEOMETRIC_SHAPES ||
          block_code == UBLOCK_MISCELLANEOUS_SYMBOLS;
 }
 
+// Returns the index of the first unusual character after a usual character or
+// vice versa. Unusual characters are defined by |IsUnusualBlockCode|.
+size_t FindUnusualCharacter(const base::string16& text,
+                            size_t run_start,
+                            size_t run_break) {
+  const int32 run_length = static_cast<int32>(run_break - run_start);
+  base::i18n::UTF16CharIterator iter(text.c_str() + run_start,
+                                     run_length);
+  const UBlockCode first_block_code = ublock_getCode(iter.get());
+  const bool first_block_unusual = IsUnusualBlockCode(first_block_code);
+  while (iter.Advance() && iter.array_pos() < run_length) {
+    const UBlockCode current_block_code = ublock_getCode(iter.get());
+    if (current_block_code != first_block_code &&
+        (first_block_unusual || IsUnusualBlockCode(current_block_code))) {
+      return run_start + iter.array_pos();
+    }
+  }
+  return run_break;
+}
+
 // If the given scripts match, returns the one that isn't USCRIPT_COMMON or
 // USCRIPT_INHERITED, i.e. the more specific one. Otherwise returns
 // USCRIPT_INVALID_CODE.
 UScriptCode ScriptIntersect(UScriptCode first, UScriptCode second) {
   if (first == second ||
       (second > USCRIPT_INVALID_CODE && second <= USCRIPT_INHERITED)) {
     return first;
   }
   if (first > USCRIPT_INVALID_CODE && first <= USCRIPT_INHERITED)
     return second;
@@ skipping 611 matching lines @@
     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.
     run_break = std::min(static_cast<size_t>(script_item_break),
                          TextIndexToLayoutIndex(style.GetRange().end()));
 
     // Break runs adjacent to character substrings in certain code blocks.
     // This avoids using their fallback fonts for more characters than needed,
     // in cases like "\x25B6 Media Title", etc. http://crbug.com/278913
-    if (run_break > run->range.start()) {
-      const size_t run_start = run->range.start();
-      const int32 run_length = static_cast<int32>(run_break - run_start);
-      base::i18n::UTF16CharIterator iter(text.c_str() + run_start,
-                                         run_length);
-      const UBlockCode first_block_code = ublock_getCode(iter.get());
-      const bool first_block_unusual = IsUnusualBlockCode(first_block_code);
-      while (iter.Advance() && iter.array_pos() < run_length) {
-        const UBlockCode current_block_code = ublock_getCode(iter.get());
-        if (current_block_code != first_block_code &&
-            (first_block_unusual || IsUnusualBlockCode(current_block_code))) {
-          run_break = run_start + iter.array_pos();
-          break;
-        }
-      }
-    }
+    if (run_break > run->range.start())
+      run_break = FindUnusualCharacter(text, run->range.start(), run_break);
 
     DCHECK(IsValidCodePointIndex(text, run_break));
     style.UpdatePosition(LayoutIndexToTextIndex(run_break));
     run->range.set_end(run_break);
 
     runs_.push_back(run);
   }
 
   // Undo the temporarily applied composition underlines and selection colors.
   UndoCompositionAndSelectionStyles();
@@ skipping 53 matching lines @@
     run->positions[i].set(run->width + x_offset, y_offset);
     run->width +=
         SkScalarRoundToInt(SkFixedToScalar(hb_positions[i].x_advance));
   }
 
   hb_buffer_destroy(buffer);
   hb_font_destroy(harfbuzz_font);
 }
 
 }  // namespace gfx