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

ui/views/window/frame_background.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/window/frame_background.h"
 
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/theme_provider.h"
 #include "ui/gfx/canvas.h"
@@ skipping 44 matching lines @@
   PaintFrameColor(canvas, view);
 
   // Draw the theme frame and overlay, if available.
   if (!theme_image_.isNull()) {
     canvas->TileImageInt(theme_image_, 0, 0, view->width(),
                          theme_image_.height());
   }
   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 =
       std::min(top_left_corner_->height(),
                view->height() - bottom_left_corner_->height());
   canvas->DrawImageInt(*top_left_corner_,
                        0, 0, top_left_corner_->width(), top_left_height,
                        0, 0, top_left_corner_->width(), top_left_height,
                        false);
   canvas->TileImageInt(*top_edge_,
@@ skipping 69 matching lines @@
                                       const View* view) const {
   // Fill the top area.
   canvas->FillRect(gfx::Rect(0, 0, view->width(), top_area_height_),
                    frame_color_);
 
   // If the window is very short, we're done.
   int remaining_height = view->height() - top_area_height_;
   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_);
   canvas->FillRect(gfx::Rect(view->width() - right_edge_->width(),
                              top_area_height_, right_edge_->width(),
                              remaining_height), frame_color_);
 
   // If the window is very narrow, we're done.
   int center_width =
       view->width() - left_edge_->width() - right_edge_->width();
   if (center_width <= 0)
     return;
 
   // Fill the bottom area.
   canvas->FillRect(gfx::Rect(left_edge_->width(),
                              view->height() - bottom_edge_->height(),
                              center_width, bottom_edge_->height()),
                              frame_color_);
 }
 
 }  // namespace views