Make browser frame square when running on windows 10 with a theme.

ui/views/window/frame_background.cc

Index: ui/views/window/frame_background.cc
diff --git a/ui/views/window/frame_background.cc b/ui/views/window/frame_background.cc
index 3e0e4ff5c06d71233c2a379e9973a6df3ab6e051..8e6466a202a096fbaa0be5731f2f5f3cee779576 100644
--- a/ui/views/window/frame_background.cc
+++ b/ui/views/window/frame_background.cc
@@ -62,6 +62,12 @@ void FrameBackground::PaintRestored(gfx::Canvas* canvas,
   if (!theme_overlay_image_.isNull())
     canvas->DrawImageInt(theme_overlay_image_, 0, 0);
 
+  if (!left_edge_ || !right_edge_ ||!bottom_edge_ || !top_edge_ ||
+      !top_left_corner_ || !top_right_corner_ || !bottom_right_corner_ ||
+      !bottom_left_corner_) {
+    return;
+  }
+
   // Draw the top corners and edge, scaling the corner images down if they
   // are too big and relative to the vertical space available.
   int top_left_height =
@@ -151,6 +157,9 @@ void FrameBackground::PaintFrameColor(gfx::Canvas* canvas,
   if (remaining_height <= 0)
     return;
 
+  if (!left_edge_ || !right_edge_ ||!bottom_edge_)
+    return;
+
   // Fill down the sides.
   canvas->FillRect(gfx::Rect(0, top_area_height_, left_edge_->width(),
                              remaining_height), frame_color_);