Consolidate RenderText adjacent word selection model code.

ui/gfx/render_text.cc

 // 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.
 
 #include "ui/gfx/render_text.h"
 
 #include <algorithm>
 
 #include "base/i18n/break_iterator.h"
 #include "base/logging.h"
@@ skipping 771 matching lines @@
   EnsureLayout();
 
   if (break_type == LINE_BREAK || text().empty())
     return EdgeSelectionModel(direction);
   if (break_type == CHARACTER_BREAK)
     return AdjacentCharSelectionModel(current, direction);
   DCHECK(break_type == WORD_BREAK);
   return AdjacentWordSelectionModel(current, direction);
 }
 
+SelectionModel RenderText::AdjacentWordSelectionModel(
+    const SelectionModel& selection,
+    VisualCursorDirection direction) {
+  if (obscured())
+    return EdgeSelectionModel(direction);
+
+  base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
+  bool success = iter.Init();
+  DCHECK(success);
+  if (!success)
+    return selection;
+
+  size_t pos = 0;
+  // TODO(msw): Cache a list of word breaks or add WordIterator functionality to
+  // start from supplied indices and to iterate backward for better performance.
+  if (direction == CURSOR_RIGHT) {
+    pos = std::min(selection.caret_pos() + 1, text().length());
+    while (iter.Advance()) {
+      pos = iter.pos();
+      if (iter.IsWord() && pos > selection.caret_pos())
+        break;
+    }
+  } else {
+    pos = std::max<int>(selection.caret_pos() - 1, 0);
+    while (iter.Advance()) {
+      if (iter.IsWord()) {
+        size_t begin = iter.pos() - iter.GetString().length();
+        if (begin == selection.caret_pos()) {
+          // The cursor is at a word beginning; move it to the previous word.
+          break;
+        } else if (iter.pos() >= selection.caret_pos()) {
+          // The cursor is at a word middle or end; move it to its beginning.
+          pos = begin;
+          break;
+        } else {
+          pos = iter.pos() - iter.GetString().length();
+        }
+      }
+    }
+  }
+  return SelectionModel(pos, CURSOR_FORWARD);
+}
+
 SelectionModel RenderText::EdgeSelectionModel(
     VisualCursorDirection direction) {
   if (direction == GetVisualDirectionOfLogicalEnd())
     return SelectionModel(text().length(), CURSOR_FORWARD);
   return SelectionModel(0, CURSOR_BACKWARD);
 }
 
 void RenderText::SetSelectionModel(const SelectionModel& model) {
   DCHECK_LE(model.selection().GetMax(), text().length());
   selection_model_ = model;
@@ skipping 212 matching lines @@
   cursor_bounds_ += delta_offset;
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   const std::vector<Rect> sel = GetSubstringBounds(selection());
   for (std::vector<Rect>::const_iterator i = sel.begin(); i < sel.end(); ++i)
     canvas->FillRect(*i, selection_background_focused_color_);
 }
 
 }  // namespace gfx