macviews: support high contrast in menus

This change:
1) Draws exterior borders on menus, even if MenuConfig says not to use them,
   if the NativeTheme is in high contrast mode;
2) Draws separators in black instead of grey in high contrast mode on Mac;
3) Draws a heavy (2pt) border around the selected item in high contrast mode
   on Mac

Screenshots are attached to the bug as comment #10.

Bug: 829347
Change-Id: I8ffd7adbae5b35751c18b77a9e8b6564926f7012
Reviewed-on: https://chromium-review.googlesource.com/1010245
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551324}

ui/native_theme/native_theme_mac.h

@@ -66,6 +66,11 @@ class NATIVE_THEME_EXPORT NativeThemeMac : public NativeThemeBase {
   NativeThemeMac();
   ~NativeThemeMac() override;
 
+  // Paint the selected menu item background, and a border for emphasis when in
+  // high contrast.
+  void PaintSelectedMenuItem(cc::PaintCanvas* canvas,
+                             const gfx::Rect& rect) const;
+
   DISALLOW_COPY_AND_ASSIGN(NativeThemeMac);
 };
 

ui/native_theme/native_theme_mac.mm

@@ -25,8 +25,6 @@
 namespace {
 
 const SkColor kMenuPopupBackgroundColor = SK_ColorWHITE;
-const SkColor kMenuSeparatorColor = SkColorSetA(SK_ColorBLACK, 38);
-const SkColor kMenuBorderColor = SkColorSetARGB(60, 0, 0, 0);
 
 // Hardcoded color used for some existing dialogs in Chrome's Cocoa UI.
 const SkColor kDialogBackgroundColor = SkColorSetRGB(251, 251, 251);
@@ -144,9 +142,11 @@ SkColor NativeThemeMac::GetSystemColor(ColorId color_id) const {
     case kColorId_MenuBackgroundColor:
       return kMenuPopupBackgroundColor;
     case kColorId_MenuSeparatorColor:
-      return kMenuSeparatorColor;
+      return UsesHighContrastColors() ? SK_ColorBLACK
+                                      : SkColorSetA(SK_ColorBLACK, 0x26);
     case kColorId_MenuBorderColor:
-      return kMenuBorderColor;
+      return UsesHighContrastColors() ? SK_ColorBLACK
+                                      : SkColorSetA(SK_ColorBLACK, 0x60);
 
     // Mac has a different "pressed button" styling because it doesn't use
     // ripples.
@@ -270,19 +270,13 @@ void NativeThemeMac::PaintMenuItemBackground(
     State state,
     const gfx::Rect& rect,
     const MenuItemExtraParams& menu_item) const {
-  cc::PaintFlags flags;
   switch (state) {
     case NativeTheme::kNormal:
     case NativeTheme::kDisabled:
       // Draw nothing over the regular background.
       break;
     case NativeTheme::kHovered:
-      // TODO(tapted): Draw a gradient, and use [NSColor currentControlTint] to
-      // pick colors. The System color "selectedMenuItemColor" is actually still
-      // blue for Graphite. And while "keyboardFocusIndicatorColor" does change,
-      // and is a good shade of gray, it's not blue enough for the Blue theme.
-      flags.setColor(GetSystemColor(kColorId_FocusedMenuItemBackgroundColor));
-      canvas->drawRect(gfx::RectToSkRect(rect), flags);
+      PaintSelectedMenuItem(canvas, rect);
       break;
     default:
       NOTREACHED();
@@ -307,4 +301,24 @@ NativeThemeMac::NativeThemeMac() {
 NativeThemeMac::~NativeThemeMac() {
 }
 
+void NativeThemeMac::PaintSelectedMenuItem(cc::PaintCanvas* canvas,
+                                           const gfx::Rect& rect) const {
+  // Draw the background.
+  cc::PaintFlags flags;
+  flags.setColor(GetSystemColor(kColorId_FocusedMenuItemBackgroundColor));
+  canvas->drawRect(gfx::RectToSkRect(rect), flags);
+
+  // In high contrast, draw a border stroke as well.
+  if (UsesHighContrastColors()) {
+    constexpr int kStrokeWidth = 2;
+    cc::PaintFlags border_flags;
+    gfx::Rect border_rect = rect;
+    border_rect.Inset(kStrokeWidth / 2, kStrokeWidth / 2);
+    border_flags.setColor(GetSystemColor(kColorId_MenuBorderColor));
+    border_flags.setStyle(cc::PaintFlags::kStroke_Style);
+    border_flags.setStrokeWidth(kStrokeWidth);
+    canvas->drawRect(gfx::RectToSkRect(border_rect), border_flags);
+  }
+}
+
 }  // namespace ui

ui/views/controls/menu/menu_scroll_view_container.cc

@@ -277,8 +277,12 @@ void MenuScrollViewContainer::CreateDefaultBorder() {
   bubble_border_ = nullptr;
 
   const MenuConfig& menu_config = MenuConfig::instance();
+  const ui::NativeTheme* native_theme = GetNativeTheme();
+  bool use_outer_border =
+      menu_config.use_outer_border ||
+      (native_theme && native_theme->UsesHighContrastColors());
 
-  int padding = menu_config.use_outer_border && menu_config.corner_radius > 0
+  int padding = use_outer_border && menu_config.corner_radius > 0
                     ? kBorderPaddingDueToRoundedCorners
                     : 0;
 
@@ -286,7 +290,7 @@ void MenuScrollViewContainer::CreateDefaultBorder() {
   const int horizontal_inset =
       menu_config.menu_horizontal_border_size + padding;
 
-  if (menu_config.use_outer_border) {
+  if (use_outer_border) {
     SkColor color = GetNativeTheme()
                         ? GetNativeTheme()->GetSystemColor(
                               ui::NativeTheme::kColorId_MenuBorderColor)