Make NativeTextfieldViews update the win system caret.

ui/base/win/accessibility_misc_utils.h

Index: ui/base/win/accessibility_misc_utils.h
diff --git a/ui/base/win/accessibility_misc_utils.h b/ui/base/win/accessibility_misc_utils.h
index 3789efb02b591e1e578a2b2016547978c49d6528..621a058f7656c4162d3a34ef302110c9e287749f 100644
--- a/ui/base/win/accessibility_misc_utils.h
+++ b/ui/base/win/accessibility_misc_utils.h
@@ -10,11 +10,19 @@
 
 #include "base/compiler_specific.h"
 #include "ui/base/ui_export.h"
+#include "ui/gfx/rect.h"
 
 namespace base {
 namespace win {
 
-  // UIA Text provider implementation for edit controls.
+// This is used when we draw our own caret. Updates the system caret rect
+// to the given bounding rectangle but makes it invisible. This allows
+// utilities that help the user find the system caret to continue to work.
+// |hwnd| should be the owning window, and |caret_rect| is in global
+// screen coordinates.
+UI_EXPORT void SetInvisibleSystemCaretRect(HWND hwnd, gfx::Rect caret_rect);
+
+// UIA Text provider implementation for edit controls.
 class UI_EXPORT UIATextProvider
     : public NON_EXPORTED_BASE(CComObjectRootEx<CComMultiThreadModel>),
       public IValueProvider,