Make NativeTextfieldViews update the win system caret.

ui/base/win/accessibility_misc_utils.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/base/win/accessibility_misc_utils.h"
 
 #include "base/logging.h"
 #include "ui/base/win/atl_module.h"
 
 namespace base {
 namespace win {
 
+void SetInvisibleSystemCaretRect(HWND hwnd, gfx::Rect caret_rect) {
+  // Create an invisible bitmap.
+  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);
+  DeleteObject(caret_bitmap);

[sky, 2013/11/07 01:34:42]

Does caret_bitmap leak if CreateCaret returns false? Also, don't we have some
scoper you can use?

[dmazzoni, 2013/11/07 20:07:14]

Good catch, done.

+}
+
 // UIA TextProvider implementation.
 UIATextProvider::UIATextProvider()
     : editable_(false) {}
 
 // static
 bool UIATextProvider::CreateTextProvider(bool editable, IUnknown** provider) {
   // Make sure ATL is initialized in this module.
   ui::win::CreateATLModuleIfNeeded();
 
   CComObject<UIATextProvider>* text_provider = NULL;
   HRESULT hr = CComObject<UIATextProvider>::CreateInstance(&text_provider);
   if (SUCCEEDED(hr)) {
     DCHECK(text_provider);
     text_provider->set_editable(editable);
     text_provider->AddRef();
     *provider = static_cast<ITextProvider*>(text_provider);
     return true;
   }
   return false;
 }
 
 STDMETHODIMP UIATextProvider::get_IsReadOnly(BOOL* read_only) {
   *read_only = !editable_;
   return S_OK;
 }
 
 }  // namespace win
 }  // namespace base