Make NativeTextfieldViews update the win system caret.

ui/base/win/accessibility_misc_utils.cc

Index: ui/base/win/accessibility_misc_utils.cc
diff --git a/ui/base/win/accessibility_misc_utils.cc b/ui/base/win/accessibility_misc_utils.cc
index 5074ce372a7999676e33c31c61a97dd09e8de279..7ca8a9cf8d2ccab5413d6e70b7789121531292c5 100644
--- a/ui/base/win/accessibility_misc_utils.cc
+++ b/ui/base/win/accessibility_misc_utils.cc
@@ -4,11 +4,29 @@
 #include "ui/base/win/accessibility_misc_utils.h"
 
 #include "base/logging.h"
+#include "base/win/scoped_gdi_object.h"
 #include "ui/base/win/atl_module.h"
 
 namespace base {
 namespace win {
 
+void SetInvisibleSystemCaretRect(HWND hwnd, gfx::Rect caret_rect) {
+  // Create an invisible bitmap.
+  base::win::ScopedGDIObject<HBITMAP> caret_bitmap(
+      CreateBitmap(1, caret_rect.height(), 1, 1, NULL));
+
+  // This destroys the previous caret (no matter what window it belonged to)
+  // and creates a new one owned by this window.
+  if (!CreateCaret(hwnd, caret_bitmap, 1, caret_rect.height()))
+    return;
+
+  ShowCaret(hwnd);
+  RECT window_rect;
+  GetWindowRect(hwnd, &window_rect);
+  SetCaretPos(caret_rect.x() - window_rect.left + 2,
+              caret_rect.y() - window_rect.top + 2);
+}
+
 // UIA TextProvider implementation.
 UIATextProvider::UIATextProvider()
     : editable_(false) {}