Fix regions generation on windows.

chrome/browser/ui/views/panels/panel_frame_view.cc

Index: chrome/browser/ui/views/panels/panel_frame_view.cc
diff --git a/chrome/browser/ui/views/panels/panel_frame_view.cc b/chrome/browser/ui/views/panels/panel_frame_view.cc
index aca6c2d6be4ba61e4d28e7d0418c88a55ad717c9..2645c57afb488fc4e2ae6355903af4e27d45fc07 100644
--- a/chrome/browser/ui/views/panels/panel_frame_view.cc
+++ b/chrome/browser/ui/views/panels/panel_frame_view.cc
@@ -355,9 +355,12 @@ void PanelFrameView::SetWindowCornerStyle(panel::CornerStyle corner_style) {
 
   gfx::Path window_mask;
   GetWindowMask(size(), &window_mask);
-  base::win::ScopedRegion new_region(gfx::CreateHRGNFromSkPath(window_mask));
+  base::win::ScopedRegion new_region;
+  if (!window_mask.isEmpty())
+    new_region.Set(gfx::CreateHRGNFromSkPath(window_mask));
 
   if (current_region_result == ERROR ||
+      new_region == NULL ||

[Wez, 2014/10/28 18:21:57]

We need to treat a NULL new region and current_region_result==ERROR as being
"equal", I think, since we expect ERROR in the case that there is no current
region.

[alex-ac, 2014/10/29 14:19:48]

Done.

       !::EqualRgn(current_region, new_region)) {
     // SetWindowRgn takes ownership of the new_region.
     ::SetWindowRgn(native_window, new_region.release(), TRUE);