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..6ebf5399f76557895d5a982a8847e70697eb775b 100644
--- a/chrome/browser/ui/views/panels/panel_frame_view.cc
+++ b/chrome/browser/ui/views/panels/panel_frame_view.cc
@@ -355,10 +355,14 @@ void PanelFrameView::SetWindowCornerStyle(panel::CornerStyle corner_style) {
 
   gfx::Path window_mask;
   GetWindowMask(size(), &window_mask);
-  base::win::ScopedRegion new_region(gfx::CreateHRGNFromSkPath(window_mask));
-
-  if (current_region_result == ERROR ||
-      !::EqualRgn(current_region, new_region)) {
+  base::win::ScopedRegion new_region;
+  if (!window_mask.isEmpty())
+    new_region.Set(gfx::CreateHRGNFromSkPath(window_mask));
+
+  const bool has_current_region = current_region != NULL;
+  const bool has_new_region = new_region != NULL;
+  if (has_current_region != has_new_region ||
+      (has_current_region && !::EqualRgn(current_region, new_region))) {
     // SetWindowRgn takes ownership of the new_region.
     ::SetWindowRgn(native_window, new_region.release(), TRUE);
   }