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

chrome/browser/ui/views/frame/opaque_browser_frame_view.cc

Index: chrome/browser/ui/views/frame/opaque_browser_frame_view.cc
diff --git a/chrome/browser/ui/views/frame/opaque_browser_frame_view.cc b/chrome/browser/ui/views/frame/opaque_browser_frame_view.cc
index 244321b0aa357f45d9cc44a5a8cd8222165f6681..a497fa46c7d13dfe6fe21c049b9e38c6db699f50 100644
--- a/chrome/browser/ui/views/frame/opaque_browser_frame_view.cc
+++ b/chrome/browser/ui/views/frame/opaque_browser_frame_view.cc
@@ -76,9 +76,9 @@ const int kResizeAreaCornerSize = 16;
 const int kIconMinimumSize = 16;
 #endif
 
-// This draws button that look like win10 window caption buttons.  The
-// foreground colour is taken from the theme itself, so that it is guaranteed
-// to provide good contrast with the background.
+// This draws buttons that look like win10 window caption buttons.  The
+// foreground colour is taken from the theme itself, to provide good contrast
+// with the background.
 class OpaqueWin10CaptionButton : public views::CustomButton {
  public:
   OpaqueWin10CaptionButton(OpaqueBrowserFrameView* parent, ViewID view_id);
@@ -477,6 +477,18 @@ void OpaqueBrowserFrameView::GetWindowMask(const gfx::Size& size,
   if (layout_->IsTitleBarCondensed() || frame()->IsFullscreen())
     return;
 
+#if defined(OS_WIN)
+  // On windows 10, windows should not have rounded frames in restored mode.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10) {
+    window_mask->moveTo(0, 0);
+    window_mask->lineTo(size.width(), 0);
+    window_mask->lineTo(size.width(), size.height());
+    window_mask->lineTo(0, size.height());
+    window_mask->close();
+    return;
+  }
+#endif
+
   views::GetDefaultWindowMask(
       size, frame()->GetCompositor()->device_scale_factor(), window_mask);
 }
@@ -657,7 +669,8 @@ void OpaqueBrowserFrameView::OnPaint(gfx::Canvas* canvas) {
   if (frame()->IsFullscreen())
     return;  // Nothing is visible, so don't bother to paint.
 
-  if (layout_->IsTitleBarCondensed())
+  const bool draw_as_maximized = layout_->IsTitleBarCondensed();
+  if (draw_as_maximized)
     PaintMaximizedFrameBorder(canvas);
   else
     PaintRestoredFrameBorder(canvas);
@@ -672,7 +685,8 @@ void OpaqueBrowserFrameView::OnPaint(gfx::Canvas* canvas) {
 
   if (IsToolbarVisible() && IsTabStripVisible())
     PaintToolbarBackground(canvas);
-  PaintClientEdge(canvas);
+  if (!draw_as_maximized)
+    PaintClientEdge(canvas);
 }
 
 // BrowserNonClientFrameView:
@@ -824,17 +838,28 @@ void OpaqueBrowserFrameView::PaintRestoredFrameBorder(
   frame_background_->set_theme_overlay_image(GetFrameOverlayImage());
   frame_background_->set_top_area_height(GetTopAreaHeight());
 
-  const ui::ThemeProvider* tp = GetThemeProvider();
-  frame_background_->SetSideImages(
-      tp->GetImageSkiaNamed(IDR_WINDOW_LEFT_SIDE),
-      tp->GetImageSkiaNamed(IDR_WINDOW_TOP_CENTER),
-      tp->GetImageSkiaNamed(IDR_WINDOW_RIGHT_SIDE),
-      tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_CENTER));
-  frame_background_->SetCornerImages(
-      tp->GetImageSkiaNamed(IDR_WINDOW_TOP_LEFT_CORNER),
-      tp->GetImageSkiaNamed(IDR_WINDOW_TOP_RIGHT_CORNER),
-      tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_LEFT_CORNER),
-      tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_RIGHT_CORNER));
+#if defined(OS_WIN)
+  // On windows 10 the frame has square corners, so no need for corner images.
+  const bool set_corners = base::win::GetVersion() < base::win::VERSION_WIN10;
+#else
+  const bool set_corners = true;
+#endif
+
+  if (set_corners) {
+    const ui::ThemeProvider* tp = GetThemeProvider();
+    frame_background_->SetSideImages(
+        tp->GetImageSkiaNamed(IDR_WINDOW_LEFT_SIDE),
+        tp->GetImageSkiaNamed(IDR_WINDOW_TOP_CENTER),
+        tp->GetImageSkiaNamed(IDR_WINDOW_RIGHT_SIDE),
+        tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_CENTER));
+
+    frame_background_->SetCornerImages(
+        tp->GetImageSkiaNamed(IDR_WINDOW_TOP_LEFT_CORNER),
+        tp->GetImageSkiaNamed(IDR_WINDOW_TOP_RIGHT_CORNER),
+        tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_LEFT_CORNER),
+        tp->GetImageSkiaNamed(IDR_WINDOW_BOTTOM_RIGHT_CORNER));
+  }
+
   frame_background_->PaintRestored(canvas, this);
 
   // Note: When we don't have a toolbar, we need to draw some kind of bottom