Cache dark mode and high contrast status in NativeTheme

This gets called a *lot* when fetching colors while painting which assumes it's cheap.

In fact, it's responsible for about 25% of paint time on Windows and ~6% on Mac (per profiling in the field).

Bug: 950063
Change-Id: I57905fffeb51b884a0e94bac28e10b05caacd180
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1565063Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Leonard Grey <lgrey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654848}

ui/native_theme/native_theme.cc

@@ -44,14 +44,32 @@ void NativeTheme::NotifyObservers() {
 NativeTheme::NativeTheme()
     : thumb_inactive_color_(0xeaeaea),
       thumb_active_color_(0xf4f4f4),
-      track_color_(0xd3d3d3) {
-}
+      track_color_(0xd3d3d3),
+      is_dark_mode_(IsForcedDarkMode()),
+      is_high_contrast_(IsForcedHighContrast()) {}
 
 NativeTheme::~NativeTheme() {}
 
 bool NativeTheme::SystemDarkModeEnabled() const {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kForceDarkMode);
+  return is_dark_mode_;
+}
+
+bool NativeTheme::UsesHighContrastColors() const {
+  return is_high_contrast_;
+}
+
+bool NativeTheme::IsForcedDarkMode() const {
+  static bool kIsForcedDarkMode =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kForceDarkMode);
+  return kIsForcedDarkMode;
+}
+
+bool NativeTheme::IsForcedHighContrast() const {
+  static bool kIsForcedHighContrast =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kForceHighContrast);
+  return kIsForcedHighContrast;
 }
 
 CaptionStyle NativeTheme::GetSystemCaptionStyle() const {

ui/native_theme/native_theme.h

@@ -415,7 +415,7 @@ class NATIVE_THEME_EXPORT NativeTheme {
 
   // Returns whether this NativeTheme uses higher-contrast colors, controlled by
   // system accessibility settings and the system theme.
-  virtual bool UsesHighContrastColors() const = 0;
+  virtual bool UsesHighContrastColors() const;
 
   // Whether OS-level dark mode (as in macOS Mojave or Windows 10) is enabled.
   virtual bool SystemDarkModeEnabled() const;
@@ -427,6 +427,16 @@ class NATIVE_THEME_EXPORT NativeTheme {
   NativeTheme();
   virtual ~NativeTheme();
 
+  // Whether high contrast is forced via command-line flag.
+  bool IsForcedHighContrast() const;
+  // Whether dark mode is forced via command-line flag.
+  bool IsForcedDarkMode() const;
+
+  void set_dark_mode(bool is_dark_mode) { is_dark_mode_ = is_dark_mode; }
+  void set_high_contrast(bool is_high_contrast) {
+    is_high_contrast_ = is_high_contrast;
+  }
+
   unsigned int thumb_inactive_color_;
   unsigned int thumb_active_color_;
   unsigned int track_color_;
@@ -435,6 +445,9 @@ class NATIVE_THEME_EXPORT NativeTheme {
   // Observers to notify when the native theme changes.
   base::ObserverList<NativeThemeObserver>::Unchecked native_theme_observers_;
 
+  bool is_dark_mode_ = false;
+  bool is_high_contrast_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(NativeTheme);
 };
 

ui/native_theme/native_theme_base.cc

@@ -264,11 +264,6 @@ gfx::Rect NativeThemeBase::GetNinePatchAperture(Part part) const {
   return gfx::Rect();
 }
 
-bool NativeThemeBase::UsesHighContrastColors() const {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kForceHighContrast);
-}
-
 NativeThemeBase::NativeThemeBase()
     : scrollbar_width_(kDefaultScrollbarWidth),
       scrollbar_button_length_(kDefaultScrollbarButtonLength) {

ui/native_theme/native_theme_base.h

@@ -36,7 +36,6 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
   bool SupportsNinePatch(Part part) const override;
   gfx::Size GetNinePatchCanvasSize(Part part) const override;
   gfx::Rect GetNinePatchAperture(Part part) const override;
-  bool UsesHighContrastColors() const override;
 
  protected:
   NativeThemeBase();

ui/native_theme/native_theme_mac.h

@@ -56,8 +56,6 @@ class NATIVE_THEME_EXPORT NativeThemeMac : public NativeThemeBase {
       State state,
       const gfx::Rect& rect,
       const MenuItemExtraParams& menu_item) const override;
-  bool UsesHighContrastColors() const override;
-  bool SystemDarkModeEnabled() const override;
 
   // Paints the styled button shape used for default controls on Mac. The basic
   // style is used for dialog buttons, comboboxes, and tabbed pane tabs.
@@ -70,9 +68,6 @@ class NATIVE_THEME_EXPORT NativeThemeMac : public NativeThemeBase {
                                         bool round_right,
                                         bool focus);
 
-  // Updates cached dark mode status and notifies observers if it has changed.
-  void UpdateDarkModeStatus();
-
  protected:
   friend class NativeTheme;
   friend class base::NoDestructor<NativeThemeMac>;
@@ -91,8 +86,6 @@ class NATIVE_THEME_EXPORT NativeThemeMac : public NativeThemeBase {
       appearance_observer_;
   id high_contrast_notification_token_;
 
-  bool is_dark_mode_ = false;
-
   DISALLOW_COPY_AND_ASSIGN(NativeThemeMac);
 };
 

ui/native_theme/native_theme_mac.mm

@@ -9,6 +9,7 @@
 
 #include "base/command_line.h"
 #include "base/mac/mac_util.h"
+#include "base/mac/scoped_block.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/macros.h"
 #import "skia/ext/skia_utils_mac.h"
@@ -29,7 +30,15 @@ bool IsDarkMode() {
         ]];
     return [appearance isEqual:NSAppearanceNameDarkAqua];
   }
+  return false;
+}
 
+bool IsHighContrast() {
+  NSWorkspace* workspace = [NSWorkspace sharedWorkspace];
+  if ([workspace respondsToSelector:@selector
+                 (accessibilityDisplayShouldIncreaseContrast)]) {
+    return workspace.accessibilityDisplayShouldIncreaseContrast;
+  }
   return false;
 }
 }  // namespace
@@ -45,13 +54,13 @@ bool IsDarkMode() {
 @end
 
 @implementation NativeThemeEffectiveAppearanceObserver {
-  ui::NativeThemeMac* owner_;
+  base::mac::ScopedBlock<void (^)()> handler_;
 }
 
-- (instancetype)initWithOwner:(ui::NativeThemeMac*)owner {
+- (instancetype)initWithHandler:(void (^)())handler {
   self = [super init];
   if (self) {
-    owner_ = owner;
+    handler_.reset([handler copy]);
     if (@available(macOS 10.14, *)) {
       [NSApp addObserver:self
               forKeyPath:@"effectiveAppearance"
@@ -73,7 +82,7 @@ bool IsDarkMode() {
                       ofObject:(id)object
                         change:(NSDictionary*)change
                        context:(void*)context {
-  owner_->UpdateDarkModeStatus();
+  handler_.get()();
 }
 
 @end
@@ -267,42 +276,31 @@ void NativeThemeMac::PaintMenuItemBackground(
   }
 }
 
-bool NativeThemeMac::UsesHighContrastColors() const {
-  if (NativeThemeBase::UsesHighContrastColors())
-    return true;
-  NSWorkspace* workspace = [NSWorkspace sharedWorkspace];
-  if ([workspace respondsToSelector:@selector
-                 (accessibilityDisplayShouldIncreaseContrast)]) {
-    return workspace.accessibilityDisplayShouldIncreaseContrast;
-  }
-  return false;
-}
-
-bool NativeThemeMac::SystemDarkModeEnabled() const {
-  if (@available(macOS 10.14, *)) {
-    return is_dark_mode_;
-  } else {
-    // Support "--force-dark-mode" in macOS < 10.14.
-    return NativeThemeBase::SystemDarkModeEnabled();
-  }
-}
-
 NativeThemeMac::NativeThemeMac() {
   if (base::FeatureList::IsEnabled(features::kDarkMode)) {
-    is_dark_mode_ = IsDarkMode();
+    __block auto theme = this;
+    set_dark_mode(IsDarkMode());
     appearance_observer_.reset(
-        [[NativeThemeEffectiveAppearanceObserver alloc] initWithOwner:this]);
+        [[NativeThemeEffectiveAppearanceObserver alloc] initWithHandler:^{
+          theme->set_dark_mode(IsDarkMode());
+          theme->NotifyObservers();
+        }]);
   }
   if (@available(macOS 10.10, *)) {
-    high_contrast_notification_token_ = [[[NSWorkspace sharedWorkspace]
-        notificationCenter]
-        addObserverForName:
-            NSWorkspaceAccessibilityDisplayOptionsDidChangeNotification
-                    object:nil
-                     queue:nil
-                usingBlock:^(NSNotification* notification) {
-                  ui::NativeTheme::GetInstanceForNativeUi()->NotifyObservers();
-                }];
+    if (!IsForcedHighContrast()) {
+      set_high_contrast(IsHighContrast());
+      __block auto theme = this;
+      high_contrast_notification_token_ =
+          [[[NSWorkspace sharedWorkspace] notificationCenter]
+              addObserverForName:
+                  NSWorkspaceAccessibilityDisplayOptionsDidChangeNotification
+                          object:nil
+                           queue:nil
+                      usingBlock:^(NSNotification* notification) {
+                        theme->set_high_contrast(IsHighContrast());
+                        theme->NotifyObservers();
+                      }];
+    }
   }
 }
 
@@ -319,11 +317,4 @@ void NativeThemeMac::PaintSelectedMenuItem(cc::PaintCanvas* canvas,
   canvas->drawRect(gfx::RectToSkRect(rect), flags);
 }
 
-void NativeThemeMac::UpdateDarkModeStatus() {
-  bool was_dark_mode = is_dark_mode_;
-  is_dark_mode_ = IsDarkMode();
-  if (was_dark_mode != is_dark_mode_)
-    NotifyObservers();
-}
-
 }  // namespace ui

ui/native_theme/native_theme_win.cc

@@ -238,9 +238,7 @@ NativeThemeWin::NativeThemeWin()
       open_theme_(NULL),
       close_theme_(NULL),
       theme_dll_(LoadLibrary(L"uxtheme.dll")),
-      color_change_listener_(this),
-      is_using_high_contrast_(false),
-      is_using_high_contrast_valid_(false) {
+      color_change_listener_(this) {
   if (theme_dll_) {
     draw_theme_ = reinterpret_cast<DrawThemeBackgroundPtr>(
         GetProcAddress(theme_dll_, "DrawThemeBackground"));
@@ -255,7 +253,9 @@ NativeThemeWin::NativeThemeWin()
     close_theme_ = reinterpret_cast<CloseThemeDataPtr>(
         GetProcAddress(theme_dll_, "CloseThemeData"));
   }
-  if (base::FeatureList::IsEnabled(features::kDarkMode)) {
+
+  if (!IsForcedDarkMode() && !IsForcedHighContrast() &&
+      base::FeatureList::IsEnabled(features::kDarkMode)) {
     // Dark Mode currently targets UWP apps, which means Win32 apps need to use
     // alternate, less reliable means of detecting the state. The following
     // can break in future Windows versions.
@@ -265,9 +265,13 @@ NativeThemeWin::NativeThemeWin()
             L"Software\\Microsoft\\Windows\\CurrentVersion\\"
             L"Themes\\Personalize",
             KEY_READ | KEY_NOTIFY) == ERROR_SUCCESS;
-    if (key_open_succeeded)
+    if (key_open_succeeded) {
+      UpdateDarkModeStatus();
       RegisterThemeRegkeyObserver();
+    }
   }
+  if (!IsForcedHighContrast())
+    set_high_contrast(IsUsingHighContrastThemeInternal());
   memset(theme_handles_, 0, sizeof(theme_handles_));
 
   // Initialize the cached system colors.
@@ -284,15 +288,10 @@ NativeThemeWin::~NativeThemeWin() {
 }
 
 bool NativeThemeWin::IsUsingHighContrastThemeInternal() const {
-  if (is_using_high_contrast_valid_)
-    return is_using_high_contrast_;
   HIGHCONTRAST result;
   result.cbSize = sizeof(HIGHCONTRAST);
-  is_using_high_contrast_ =
-      SystemParametersInfo(SPI_GETHIGHCONTRAST, result.cbSize, &result, 0) &&
-      (result.dwFlags & HCF_HIGHCONTRASTON) == HCF_HIGHCONTRASTON;
-  is_using_high_contrast_valid_ = true;
-  return is_using_high_contrast_;
+  return SystemParametersInfo(SPI_GETHIGHCONTRAST, result.cbSize, &result, 0) &&
+         (result.dwFlags & HCF_HIGHCONTRASTON) == HCF_HIGHCONTRASTON;
 }
 
 void NativeThemeWin::CloseHandlesInternal() {
@@ -309,7 +308,8 @@ void NativeThemeWin::CloseHandlesInternal() {
 
 void NativeThemeWin::OnSysColorChange() {
   UpdateSystemColors();
-  is_using_high_contrast_valid_ = false;
+  if (!IsForcedHighContrast())
+    set_high_contrast(IsUsingHighContrastThemeInternal());
   NotifyObservers();
 }
 
@@ -579,26 +579,13 @@ gfx::Rect NativeThemeWin::GetNinePatchAperture(Part part) const {
   return gfx::Rect();
 }
 
-bool NativeThemeWin::UsesHighContrastColors() const {
-  bool force_enabled = base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kForceHighContrast);
-  return force_enabled || IsUsingHighContrastThemeInternal();
-}
-
 bool NativeThemeWin::SystemDarkModeEnabled() const {
   // Windows high contrast modes are entirely different themes,
   // so let them take priority over dark mode.
   // ...unless --force-dark-mode was specified in which case caveat emptor.
-  if (UsesHighContrastColors() && !NativeTheme::SystemDarkModeEnabled())
+  if (UsesHighContrastColors() && !IsForcedDarkMode())
     return false;
-  bool fDarkModeEnabled = false;
-  if (hkcu_themes_regkey_.Valid()) {
-    DWORD apps_use_light_theme = 1;
-    hkcu_themes_regkey_.ReadValueDW(L"AppsUseLightTheme",
-                                    &apps_use_light_theme);
-    fDarkModeEnabled = (apps_use_light_theme == 0);
-  }
-  return fDarkModeEnabled || NativeTheme::SystemDarkModeEnabled();
+  return NativeTheme::SystemDarkModeEnabled();
 }
 
 void NativeThemeWin::PaintIndirect(cc::PaintCanvas* destination_canvas,
@@ -1933,6 +1920,7 @@ void NativeThemeWin::RegisterThemeRegkeyObserver() {
   DCHECK(hkcu_themes_regkey_.Valid());
   hkcu_themes_regkey_.StartWatching(base::BindOnce(
       [](NativeThemeWin* native_theme) {
+        native_theme->UpdateDarkModeStatus();
         native_theme->NotifyObservers();
         // RegKey::StartWatching only provides one notification. Reregistration
         // is required to get future notifications.
@@ -1941,4 +1929,15 @@ void NativeThemeWin::RegisterThemeRegkeyObserver() {
       base::Unretained(this)));
 }
 
+void NativeThemeWin::UpdateDarkModeStatus() {
+  bool fDarkModeEnabled = false;
+  if (hkcu_themes_regkey_.Valid()) {
+    DWORD apps_use_light_theme = 1;
+    hkcu_themes_regkey_.ReadValueDW(L"AppsUseLightTheme",
+                                    &apps_use_light_theme);
+    fDarkModeEnabled = (apps_use_light_theme == 0);
+  }
+  set_dark_mode(fDarkModeEnabled);
+}
+
 }  // namespace ui

ui/native_theme/native_theme_win.h

@@ -80,7 +80,6 @@ class NATIVE_THEME_EXPORT NativeThemeWin : public NativeTheme,
   bool SupportsNinePatch(Part part) const override;
   gfx::Size GetNinePatchCanvasSize(Part part) const override;
   gfx::Rect GetNinePatchAperture(Part part) const override;
-  bool UsesHighContrastColors() const override;
   bool SystemDarkModeEnabled() const override;
 
  protected:
@@ -263,6 +262,7 @@ class NATIVE_THEME_EXPORT NativeThemeWin : public NativeTheme,
   HANDLE GetThemeHandle(ThemeName theme_name) const;
 
   void RegisterThemeRegkeyObserver();
+  void UpdateDarkModeStatus();
 
   typedef HRESULT (WINAPI* DrawThemeBackgroundPtr)(HANDLE theme,
                                                    HDC hdc,
@@ -328,12 +328,6 @@ class NATIVE_THEME_EXPORT NativeThemeWin : public NativeTheme,
   gfx::ScopedSysColorChangeListener color_change_listener_;
   mutable std::map<int, SkColor> system_colors_;
 
-  // Is a high contrast theme active?
-  mutable bool is_using_high_contrast_;
-
-  // Is |is_using_high_contrast_| valid?
-  mutable bool is_using_high_contrast_valid_;
-
   DISALLOW_COPY_AND_ASSIGN(NativeThemeWin);
 };