Fix increased contrast toggling

This CL fixes the theme service to be able to toggle native increased
contrast support.
We were not considering IncreasedContrastThemeSupplier as a default
theme and were not removing it when native increased contrast was
disabled.

Bug: 1056335
Change-Id: I42b59e58912de8224b3d7d4e84fb355cd7851dc5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2078376
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Auto-Submit: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746686}

chrome/browser/themes/browser_theme_pack.h

@@ -281,6 +281,8 @@ class BrowserThemePack : public CustomThemeSupplier {
   void GenerateRawImageForAllSupportedScales(int prs_id);
 
   // Data pack, if we have one.
+  // TODO(crbug.com/1057889): Destroy this on in the thread pool, make the rest
+  // of CustomThemeSupplier destruction synchronous.
   std::unique_ptr<ui::DataPack> data_pack_;
 
   // All structs written to disk need to be packed; no alignment tricks here,

chrome/browser/themes/theme_helper.cc

@@ -89,12 +89,20 @@ bool ThemeHelper::IsAutogeneratedTheme(
 bool ThemeHelper::IsDefaultTheme(const CustomThemeSupplier* theme_supplier) {
   if (!theme_supplier)
     return true;
-  if (theme_supplier->get_theme_type() !=
-      CustomThemeSupplier::ThemeType::EXTENSION) {
-    return false;
+
+  using Type = CustomThemeSupplier::ThemeType;
+
+  switch (theme_supplier->get_theme_type()) {
+    case Type::INCREASED_CONTRAST:
+      return true;
+    case Type::EXTENSION: {
+      const std::string& id = theme_supplier->extension_id();
+      return id == kDefaultThemeID || id == kDefaultThemeGalleryID;
+    }
+    case Type::NATIVE_X11:
+    case Type::AUTOGENERATED:
+      return false;
   }
-  const std::string& id = theme_supplier->extension_id();
-  return id == kDefaultThemeID || id == kDefaultThemeGalleryID;
 }
 
 // static

chrome/browser/themes/theme_service.h

@@ -154,6 +154,8 @@ class ThemeService : public content::NotificationObserver,
   std::unique_ptr<ThemeService::ThemeReinstaller>
   BuildReinstallerForCurrentTheme();
 
+  const ThemeHelper& theme_helper_for_testing() const { return theme_helper_; }
+
  protected:
   // Set a custom default theme instead of the normal default theme.
   virtual void SetCustomDefaultTheme(

chrome/browser/themes/theme_service_unittest.cc

@@ -585,4 +585,25 @@ TEST_F(ThemeServiceTest, TranslucentOmniboxBackgroundAndText) {
   }
 }
 
+TEST_F(ThemeServiceTest, NativeIncreasedContrastChanged) {
+  theme_service_->UseDefaultTheme();
+
+  native_theme_.SetUsesHighContrastColors(true);
+  theme_service_->OnNativeThemeUpdated(&native_theme_);
+  EXPECT_TRUE(theme_service_->UsingDefaultTheme());
+  bool using_increased_contrast =
+      theme_service_->GetThemeSupplier() &&
+      theme_service_->GetThemeSupplier()->get_theme_type() ==
+          CustomThemeSupplier::ThemeType::INCREASED_CONTRAST;
+  bool expecting_increased_contrast =
+      theme_service_->theme_helper_for_testing()
+          .ShouldUseIncreasedContrastThemeSupplier(&native_theme_);
+  EXPECT_EQ(using_increased_contrast, expecting_increased_contrast);
+
+  native_theme_.SetUsesHighContrastColors(false);
+  theme_service_->OnNativeThemeUpdated(&native_theme_);
+  EXPECT_TRUE(theme_service_->UsingDefaultTheme());
+  EXPECT_EQ(theme_service_->GetThemeSupplier(), nullptr);
+}
+
 }  // namespace theme_service_internal