Restore NativeWidgetWin::OnSetIcon to eliminate classic theme titlebar flickering.

ui/views/widget/native_widget_win.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/views/widget/native_widget_win.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
 
 #include <algorithm>
@@ skipping 1988 matching lines @@
 }
 
 void NativeWidgetWin::OnSetFocus(HWND old_focused_window) {
   delegate_->OnNativeFocus(old_focused_window);
   InputMethod* input_method = GetWidget()->GetInputMethodDirect();
   if (input_method)
     input_method->OnFocus();
   SetMsgHandled(FALSE);
 }
 
+LRESULT NativeWidgetWin::OnSetIcon(UINT size_type, HICON new_icon) {
+  // Use a ScopedRedrawLock to avoid weird non-client painting.
+  return DefWindowProcWithRedrawLock(WM_SETICON, size_type,
+                                     reinterpret_cast<LPARAM>(new_icon));
+}
+
 LRESULT NativeWidgetWin::OnSetText(const wchar_t* text) {
-  // DefWindowProc for WM_SETTEXT does weird non-client painting, so we need to
-  // call it inside a ScopedRedrawLock.
+  // Use a ScopedRedrawLock to avoid weird non-client painting.
   return DefWindowProcWithRedrawLock(WM_SETTEXT, NULL,
                                      reinterpret_cast<LPARAM>(text));
 }
 
 void NativeWidgetWin::OnSettingChange(UINT flags, const wchar_t* section) {
   if (!GetParent() && (flags == SPI_SETWORKAREA) &&
       !GetWidget()->widget_delegate()->WillProcessWorkAreaChange()) {
     // Fire a dummy SetWindowPos() call, so we'll trip the code in
     // OnWindowPosChanging() below that notices work area changes.
     ::SetWindowPos(GetNativeView(), 0, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE |
@@ skipping 739 matching lines @@
 // static
 bool NativeWidgetPrivate::IsTouchDown() {
   // This currently isn't necessary because we're not generating touch events on
   // windows.  When we do, this will need to be updated.
   return false;
 }
 
 }  // namespace internal
 
 }  // namespace views