Adjust |index| into cursorable position in NativeTextfieldViews::GetCompositionCharacterBounds

RenderText::GetCursorBounds expects that that |caret| parameter is placed at somewhere cursorable so far. In fact, tt has a DCHECK like this: DCHECK(IsCursorablePosition(caret_pos)).

On the other hand, currently NativeTextfieldViews::GetCompositionCharacterBounds(index, ...) is implemented by calling RenderText::GetCursorBounds with |index| and |index + 1|.  This may cause DCHECK failure because neither |index| nor |index + 1| is guaranteed to be cursorable position.

This CL updates NativeTextfieldViews::GetCompositionCharacterBounds to make sure that RenderText::GetCursorBounds is called with cursorable position.

This CL also fixes a comment bug in RenderText::GetCursorBounds().

BUG=325083
TEST=views_unitetest --gtest_filter=NativeTextfieldViewsTest.*

Review URL: https://codereview.chromium.org/101603002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238686 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 10 deletions

diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index bafe6af..8696d69 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -354,12 +354,19 @@ class GFX_EXPORT RenderText {
   // Gets the SelectionModel from a visual point in local coordinates.
   virtual SelectionModel FindCursorPosition(const Point& point) = 0;
 
-  // Get the visual bounds of a cursor at |selection|. These bounds typically
-  // represent a vertical line, but if |insert_mode| is true they contain the
-  // bounds of the associated glyph. These bounds are in local coordinates, but
-  // may be outside the visible region if the text is longer than the textfield.
-  // Subsequent text, cursor, or bounds changes may invalidate returned values.
-  Rect GetCursorBounds(const SelectionModel& selection, bool insert_mode);
+  // 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;
+
+  // Get the visual bounds of a cursor at |caret|. These bounds typically
+  // represent a vertical line if |insert_mode| is true. Pass false for
+  // |insert_mode| to retrieve the bounds of the associated glyph. These bounds
+  // are in local coordinates, but may be outside the visible region if the text
+  // is longer than the textfield. Subsequent text, cursor, or bounds changes
+  // may invalidate returned values. Note that |caret| must be placed at
+  // grapheme boundary, that is, |IsCursorablePosition(caret.caret_pos())| must
+  // return true.
+  Rect GetCursorBounds(const SelectionModel& caret, bool insert_mode);
 
   // Compute the current cursor bounds, panning the text to show the cursor in
   // the display rect if necessary. These bounds are in local coordinates.
@@ -473,10 +480,6 @@ class GFX_EXPORT RenderText {
   virtual size_t TextIndexToLayoutIndex(size_t index) const = 0;
   virtual size_t LayoutIndexToTextIndex(size_t index) const = 0;
 
-  // 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;
-
   // Reset the layout to be invalid.
   virtual void ResetLayout() = 0;