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

ui/gfx/render_text_mac.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_mac.h"
 
 #include <ApplicationServices/ApplicationServices.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 73 matching lines @@
   return index;
 }
 
 size_t RenderTextMac::LayoutIndexToTextIndex(size_t index) const {
   // TODO(asvitkine): Implement this. http://crbug.com/131618
   return index;
 }
 
 bool RenderTextMac::IsCursorablePosition(size_t position) {
   // TODO(asvitkine): Implement this. http://crbug.com/131618
-  return false;
+  return true;
 }
 
 void RenderTextMac::ResetLayout() {
   line_.reset();
   attributes_.reset();
   runs_.clear();
   runs_valid_ = false;
 }
 
 void RenderTextMac::EnsureLayout() {
@@ skipping 214 matching lines @@
     run_origin.offset(run_width, 0);
   }
   runs_valid_ = true;
 }
 
 RenderText* RenderText::CreateInstance() {
   return new RenderTextMac;
 }
 
 }  // namespace gfx