Native themes: Add menu separator part

ui/views/controls/menu/menu_separator.cc

Index: ui/views/controls/menu/menu_separator.cc
diff --git a/ui/views/controls/menu/menu_separator_views.cc b/ui/views/controls/menu/menu_separator.cc
similarity index 64%
rename from ui/views/controls/menu/menu_separator_views.cc
rename to ui/views/controls/menu/menu_separator.cc
index 86f794ad0af5cc7150b916cdc71395effdfc1537..d3d532e2fb5d7f6d75232bc207845dda4e276378 100644
--- a/ui/views/controls/menu/menu_separator_views.cc
+++ b/ui/views/controls/menu/menu_separator.cc
@@ -10,58 +10,72 @@
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/controls/menu/menu_config.h"
 
+#if defined(OS_WIN)
+#include "ui/display/win/dpi.h"
+#endif
+
 namespace views {
 
-#if !defined(OS_WIN)
 void MenuSeparator::OnPaint(gfx::Canvas* canvas) {
-  canvas->FillRect(GetPaintBounds(),
-                   GetNativeTheme()->GetSystemColor(
-                       ui::NativeTheme::kColorId_MenuSeparatorColor));
-}
-#endif
+  if (type_ == ui::SPACING_SEPARATOR)
+    return;
 
-gfx::Size MenuSeparator::GetPreferredSize() const {
   const MenuConfig& menu_config = MenuConfig::instance();
-  int height = menu_config.separator_height;
-  switch(type_) {
-    case ui::SPACING_SEPARATOR:
-      height = menu_config.separator_spacing_height;
-      break;
+  int pos = 0;
+  int separator_thickness = menu_config.separator_thickness;
+  switch (type_) {
     case ui::LOWER_SEPARATOR:
-      height = menu_config.separator_lower_height;
+      pos = height() - separator_thickness;
       break;
     case ui::UPPER_SEPARATOR:
-      height = menu_config.separator_upper_height;
       break;
     default:
-      height = menu_config.separator_height;
+      pos = height() / 2;
       break;
   }
-  return gfx::Size(10,  // Just in case we're the only item in a menu.
-                   height);
+
+  gfx::Rect paint_rect(0, pos, width(), separator_thickness);
+  if (menu_config.use_outer_border)
+    paint_rect.Inset(1, 0);
+
+#if defined(OS_WIN)
+  // Hack to get the separator to display correctly on Windows where we may
+  // have fractional scales. We move the separator 1 pixel down to ensure that
+  // it falls within the clipping rect which is scaled up.
+  float device_scale = display::win::GetDPIScale();
+  bool is_fractional_scale =
+      (device_scale - static_cast<int>(device_scale) != 0);
+  if (is_fractional_scale && paint_rect.y() == 0)
+    paint_rect.set_y(1);
+#endif
+
+  ui::NativeTheme::ExtraParams params;
+  params.menu_separator.paint_rect = &paint_rect;
+  params.menu_separator.type = type_;
+  GetNativeTheme()->Paint(
+      canvas->sk_canvas(), ui::NativeTheme::kMenuPopupSeparator,
+      ui::NativeTheme::kNormal, gfx::Rect(bounds().size()), params);
 }
 
-gfx::Rect MenuSeparator::GetPaintBounds() {
-  int pos = 0;
+gfx::Size MenuSeparator::GetPreferredSize() const {
   const MenuConfig& menu_config = MenuConfig::instance();
-  int separator_thickness = menu_config.separator_thickness;
+  int height = menu_config.separator_height;
   switch (type_) {
+    case ui::SPACING_SEPARATOR:
+      height = menu_config.separator_spacing_height;
+      break;
     case ui::LOWER_SEPARATOR:
-      pos = height() - separator_thickness;
+      height = menu_config.separator_lower_height;
       break;
-    case ui::SPACING_SEPARATOR:
-      return gfx::Rect();
     case ui::UPPER_SEPARATOR:
+      height = menu_config.separator_upper_height;
       break;
     default:
-      pos = height() / 2;
+      height = menu_config.separator_height;
       break;
   }
-
-  gfx::Rect paint_rect(0, pos, width(), separator_thickness);
-  if (menu_config.use_outer_border)
-    paint_rect.Inset(1, 0);
-  return paint_rect;
+  return gfx::Size(10,  // Just in case we're the only item in a menu.
+                   height);
 }
 
 }  // namespace views