This is a reapply of

http://src.chromium.org/viewvc/chrome?view=rev&revision=102006

fix know issues in RenderText

1. add tests.
2. change SelectWord() to use BreakIterator, so it works for Chinese and Complex script.
3. DELETE/ReplaceChar delete/replace a whole grapheme. ReplaceTextInternal should only replace one grapheme when there is no selection.
4. pointing to position outside of text returns HOME/END position.
5. based on Chrome Linux omnibox and gedit, given 
"abc|   def", double click should select "   " instead of "abc". Change test expectation.

BUG=90426
TEST=compile with touchui=1 test omnibox. run views_unittests.NativeTextfieldViewsTest/TextfieldViewsModelTest
Review URL: http://codereview.chromium.org/7841056

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102160 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 16 insertions, 3 deletions

diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index 82eab91..4a1f9a9 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -193,7 +193,9 @@ class UI_EXPORT RenderText {
   // Set the selection_model_ to the value of |selection|.
   // The selection model components are modified if invalid.
   // Returns true if the cursor position or selection range changed.
-  // TODO(xji): need to check the cursor is set at grapheme boundary.
+  // If |selectin_start_| or |selection_end_| or |caret_pos_| in
+  // |selection_model| is not a cursorable position (not on grapheme boundary),
+  // it is a NO-OP and returns false.
   bool MoveCursorTo(const SelectionModel& selection_model);
 
   // Move the cursor to the position associated with the clicked point.
@@ -254,6 +256,9 @@ class UI_EXPORT RenderText {
   // Subsequent text, cursor, or bounds changes may invalidate returned values.
   const Rect& GetUpdatedCursorBounds();
 
+  // Get the logical index of the grapheme following the argument |position|.
+  virtual size_t GetIndexOfNextGrapheme(size_t position);
+
  protected:
   RenderText();
 
@@ -288,6 +293,10 @@ class UI_EXPORT RenderText {
   // TODO(msw) Re-evaluate this function's necessity and signature.
   virtual std::vector<Rect> GetSubstringBounds(size_t from, size_t to);
 
+  // Return true if cursor can appear in front of the character at |position|,
+  // which means it is a grapheme boundary or the first character in the text.
+  virtual bool IsCursorablePosition(size_t position) = 0;
+
   // Apply composition style (underline) to composition range and selection
   // style (foreground) to selection range.
   void ApplyCompositionAndSelectionStyles(StyleRanges* style_ranges) const;
@@ -305,16 +314,20 @@ class UI_EXPORT RenderText {
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ApplyStyleRange);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, StyleRangesAdjust);
 
+  // Return an index belonging to the |next| or previous logical grapheme.
+  // The return value is bounded by 0 and the text length, inclusive.
+  virtual size_t IndexOfAdjacentGrapheme(size_t index, bool next) = 0;
+
   // Sets the selection model, the argument is assumed to be valid.
   void SetSelectionModel(const SelectionModel& selection_model);
 
   // Set the cursor to |position|, with the caret trailing the previous
   // grapheme, or if there is no previous grapheme, leading the cursor position.
   // If |select| is false, the selection start is moved to the same position.
+  // If the |position| is not a cursorable position (not on grapheme boundary),
+  // it is a NO-OP.
   void MoveCursorTo(size_t position, bool select);
 
-  bool IsPositionAtWordSelectionBoundary(size_t pos);
-
   // Update the cached bounds and display offset to ensure that the current
   // cursor is within the visible display area.
   void UpdateCachedBoundsAndOffset();