Re-land: NativeTextfieldViews: Show the drop cursor when dragging text

ui/gfx/render_text.cc

Index: ui/gfx/render_text.cc
diff --git a/ui/gfx/render_text.cc b/ui/gfx/render_text.cc
index fc9353f682f79ae48a19638650539c8275a629cd..4388b6d1db817dcbeb03acc6d64f65de1f38505d 100644
--- a/ui/gfx/render_text.cc
+++ b/ui/gfx/render_text.cc
@@ -611,7 +611,8 @@ void RenderText::Draw(Canvas* canvas) {
   if (!text().empty())
     DrawSelection(canvas);
 
-  DrawCursor(canvas);
+  if (cursor_enabled() && cursor_visible() && focused())
+    DrawCursor(canvas, selection_model_);
 
   if (!text().empty())
     DrawVisualText(canvas);
@@ -620,6 +621,12 @@ void RenderText::Draw(Canvas* canvas) {
     canvas->Restore();
 }
 
+void RenderText::DrawCursor(Canvas* canvas, const SelectionModel& position) {
+  // Paint cursor. Replace cursor is drawn as rectangle for now.
+  // TODO(msw): Draw a better cursor with a better indication of association.
+  canvas->FillRect(GetCursorBounds(position, true), cursor_color_);
+}
+
 void RenderText::DrawSelectedText(Canvas* canvas) {
   EnsureLayout();
   const std::vector<Rect> sel = GetSubstringBounds(selection());
@@ -636,6 +643,7 @@ Rect RenderText::GetCursorBounds(const SelectionModel& caret,
   EnsureLayout();
 
   size_t caret_pos = caret.caret_pos();
+  DCHECK(IsCursorablePosition(caret_pos));
   // In overtype mode, ignore the affinity and always indicate that we will
   // overtype the next character.
   LogicalCursorDirection caret_affinity =
@@ -963,13 +971,4 @@ void RenderText::DrawSelection(Canvas* canvas) {
     canvas->FillRect(*i, color);
 }
 
-void RenderText::DrawCursor(Canvas* canvas) {
-  // Paint cursor. Replace cursor is drawn as rectangle for now.
-  // TODO(msw): Draw a better cursor with a better indication of association.
-  if (cursor_enabled() && cursor_visible() && focused()) {
-    canvas->FillRect(GetUpdatedCursorBounds(),
-        insert_mode_ ? cursor_color_ : selection_background_unfocused_color_);
-  }
-}
-
 }  // namespace gfx