Fix for 593676 - Minimizes/eliminates momentary flash of Windows frame

ui/views/win/hwnd_message_handler.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/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <tchar.h>
@@ skipping 2308 matching lines @@
 
   SetMsgHandled(FALSE);
 }
 
 void HWNDMessageHandler::OnWindowPosChanged(WINDOWPOS* window_pos) {
   if (DidClientAreaSizeChange(window_pos))
     ClientAreaSizeChanged();
   if (!delegate_->HasFrame() && window_pos->flags & SWP_FRAMECHANGED &&
       ui::win::IsAeroGlassEnabled() &&
       (window_ex_style() & WS_EX_COMPOSITED) == 0) {
-    MARGINS m = {10, 10, 10, 10};
+    MARGINS m = {1, 1, 1, 1};

[kylix_rd, 2016/04/25 21:42:13]

I've uploaded this change for discussion purposes. Using blame, I traced this
code back to ben@chromium.org. This is the code that is responsible for
producing the "ghosted" frame effect. I have no idea how those magic values were
chosen, and seem arbitrary. 

I can reduce it by changing to the above margins, however it is still visible.
Changing the above to 0, will eliminate the ghosting, but then be back to no
active window highlight/shadow.

Changing to -1 for all dimensions enables "sheet-of-glass" mode, which then
causes the ghost effect to encompass the whole window. This is even more visibly
apparent.

I suspect the actual issue is being caused by the delay between creating and
showing the top-level window and the construction and rendering of the child
window for the content. When closing the window, the child window appears to be
hidden prior to destroying the top-level window. If the child window can be made
to follow the visibility of the parent window, I suspect that will solve the
issue.

     DwmExtendFrameIntoClientArea(hwnd(), &m);
   }
   if (window_pos->flags & SWP_SHOWWINDOW) {
     delegate_->HandleVisibilityChanged(true);
     if (direct_manipulation_helper_)
       direct_manipulation_helper_->Activate(hwnd());
   } else if (window_pos->flags & SWP_HIDEWINDOW) {
     delegate_->HandleVisibilityChanged(false);
     if (direct_manipulation_helper_)
       direct_manipulation_helper_->Deactivate(hwnd());
@@ skipping 339 matching lines @@
     delegate_->HandleClientSizeChanged(GetClientAreaBounds().size());
     ResetWindowRegion(false, true);
   }
 
   if (direct_manipulation_helper_)
     direct_manipulation_helper_->SetBounds(bounds_in_pixels);
 }
 
 
 }  // namespace views