Add feature flag to toggle dark mode blocking when fingerprinting=strict

browser/brave_content_browser_client.cc

@@ -37,6 +37,7 @@
 #include "brave/components/brave_shields/browser/brave_shields_util.h"
 #include "brave/components/brave_shields/browser/domain_block_navigation_throttle.h"
 #include "brave/components/brave_shields/common/brave_shield_constants.h"
+#include "brave/components/brave_shields/common/features.h"
 #include "brave/components/brave_wallet/common/buildflags/buildflags.h"
 #include "brave/components/brave_webtorrent/browser/buildflags/buildflags.h"
 #include "brave/components/cosmetic_filters/browser/cosmetic_filters_resources.h"
@@ -698,7 +699,9 @@ bool BraveContentBrowserClient::OverrideWebPreferencesAfterNavigation(
       HostContentSettingsMapFactory::GetForProfile(profile), url);
   // https://github.com/brave/brave-browser/issues/15265
   // Always use color scheme Light if fingerprinting mode strict
-  if (shields_up && fingerprinting_type == ControlType::BLOCK) {
+  if (base::FeatureList::IsEnabled(
+          brave_shields::features::kBraveDarkModeBlock) &&
+      shields_up && fingerprinting_type == ControlType::BLOCK) {
     prefs->preferred_color_scheme = blink::mojom::PreferredColorScheme::kLight;
     changed = true;
   }

browser/farbling/brave_dark_mode_fingerprint_protection_browsertest.cc

@@ -6,13 +6,15 @@
 #include "base/path_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/task/post_task.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/test/thread_test_helper.h"
 #include "brave/browser/brave_content_browser_client.h"
 #include "brave/browser/extensions/brave_base_local_data_files_browsertest.h"
 #include "brave/common/brave_paths.h"
 #include "brave/common/pref_names.h"
 #include "brave/components/brave_component_updater/browser/local_data_files_service.h"
 #include "brave/components/brave_shields/browser/brave_shields_util.h"
+#include "brave/components/brave_shields/common/features.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_content_client.h"
@@ -25,13 +27,14 @@
 #include "ui/native_theme/test_native_theme.h"
 
 using brave_shields::ControlType;
+using brave_shields::features::kBraveDarkModeBlock;
 
 const char kEmbeddedTestServerDirectory[] = "dark_mode_block";
 const char kMatchDarkMode[] =
     "window.domAutomationController.send(window.matchMedia('(prefers-color-"
     "scheme: dark)').matches)";
 
-class BraveDarkModeFingerprintProtection : public InProcessBrowserTest {
+class BraveDarkModeFingerprintProtectionTest : public InProcessBrowserTest {
  public:
   class BraveContentBrowserClientWithWebTheme
       : public BraveContentBrowserClient {
@@ -106,7 +109,7 @@ class BraveDarkModeFingerprintProtection : public InProcessBrowserTest {
   GURL dark_mode_url_;
 };
 
-IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, DarkModeCheck) {
+IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtectionTest, DarkModeCheck) {
   test_theme_.SetDarkMode(true);
   // On fingerprinting off, should return dark mode
   AllowFingerprinting();
@@ -126,7 +129,8 @@ IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, DarkModeCheck) {
   EXPECT_EQ(u"light", tab_title);
 }
 
-IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, RegressionCheck) {
+IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtectionTest,
+                       RegressionCheck) {
   test_theme_.SetDarkMode(false);
   // On all modes, should return light
   // Fingerprinting off
@@ -147,7 +151,8 @@ IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, RegressionCheck) {
   EXPECT_EQ(u"light", tab_title);
 }
 
-IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, SettingsPagesCheck) {
+IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtectionTest,
+                       SettingsPagesCheck) {
   // On settings page should get dark mode with fingerprinting strict
   test_theme_.SetDarkMode(true);
   BlockFingerprinting();
@@ -157,3 +162,35 @@ IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtection, SettingsPagesCheck) {
                                                    &result));
   EXPECT_TRUE(result);
 }
+
+class BraveDarkModeFingerprintProtectionFlagDisabledTest
+    : public BraveDarkModeFingerprintProtectionTest {
+ public:
+  BraveDarkModeFingerprintProtectionFlagDisabledTest() {
+    feature_list_.InitAndDisableFeature(kBraveDarkModeBlock);
+  }
+
+ private:
+  base::test::ScopedFeatureList feature_list_;
+};
+
+IN_PROC_BROWSER_TEST_F(BraveDarkModeFingerprintProtectionFlagDisabledTest,
+                       WithFeatureDisabled) {
+  test_theme_.SetDarkMode(true);
+  // On fingerprinting off, should return dark mode
+  AllowFingerprinting();
+  NavigateToURLUntilLoadStop(dark_mode_url());
+  std::u16string tab_title;
+  ASSERT_TRUE(ui_test_utils::GetCurrentTabTitle(browser(), &tab_title));
+  EXPECT_EQ(u"dark", tab_title);
+  // On fingerprinting default, should return dark mode
+  SetFingerprintingDefault();
+  NavigateToURLUntilLoadStop(dark_mode_url());
+  ASSERT_TRUE(ui_test_utils::GetCurrentTabTitle(browser(), &tab_title));
+  EXPECT_EQ(u"dark", tab_title);
+  // On fingerprinting block, should still return dark
+  BlockFingerprinting();
+  NavigateToURLUntilLoadStop(dark_mode_url());
+  ASSERT_TRUE(ui_test_utils::GetCurrentTabTitle(browser(), &tab_title));
+  EXPECT_EQ(u"dark", tab_title);
+}

chromium_src/chrome/browser/about_flags.cc

@@ -30,6 +30,7 @@ using brave_shields::features::kBraveAdblockCollapseBlockedElements;
 using brave_shields::features::kBraveAdblockCosmeticFiltering;
 using brave_shields::features::kBraveAdblockCosmeticFilteringNative;
 using brave_shields::features::kBraveAdblockCspRules;
+using brave_shields::features::kBraveDarkModeBlock;
 using brave_shields::features::kBraveDomainBlock;
 using brave_shields::features::kBraveExtensionNetworkBlocking;
 using ntp_background_images::features::kBraveNTPBrandedWallpaper;
@@ -172,6 +173,10 @@ using ntp_background_images::features::kBraveNTPSuperReferralWallpaper;
      flag_descriptions::kBraveExtensionNetworkBlockingName,                 \
      flag_descriptions::kBraveExtensionNetworkBlockingDescription, kOsAll,  \
      FEATURE_VALUE_TYPE(kBraveExtensionNetworkBlocking)},                   \
+    {"brave-dark-mode-block",                                               \
+     flag_descriptions::kBraveDarkModeBlockName,                            \
+     flag_descriptions::kBraveDarkModeBlockDescription, kOsAll,             \
+     FEATURE_VALUE_TYPE(kBraveDarkModeBlock)},                              \
     SPEEDREADER_FEATURE_ENTRIES                                             \
     BRAVE_SYNC_FEATURE_ENTRIES                                              \
     BRAVE_IPFS_FEATURE_ENTRIES                                              \

chromium_src/chrome/browser/flag_descriptions.cc

@@ -48,6 +48,10 @@ const char kBraveExtensionNetworkBlockingName[] =
     "Enable extension network blocking";
 const char kBraveExtensionNetworkBlockingDescription[] =
     "Enable blocking for network requests initiated by extensions";
+const char kBraveDarkModeBlockName[] =
+    "Enable dark mode blocking fingerprinting protection";
+const char kBraveDarkModeBlockDescription[] =
+    "Always report light mode when fingerprinting protections set to Strict";
 const char kBraveSidebarName[] = "Enable Sidebar";
 // TODO(simon): Use more better description.
 const char kBraveSidebarDescription[] = "Enable Sidebar";

chromium_src/chrome/browser/flag_descriptions.h

@@ -31,6 +31,8 @@ extern const char kBraveDomainBlockName[];
 extern const char kBraveDomainBlockDescription[];
 extern const char kBraveExtensionNetworkBlockingName[];
 extern const char kBraveExtensionNetworkBlockingDescription[];
+extern const char kBraveDarkModeBlockName[];
+extern const char kBraveDarkModeBlockDescription[];
 extern const char kBraveSidebarName[];
 extern const char kBraveSidebarDescription[];
 extern const char kBraveSpeedreaderName[];

components/brave_shields/common/features.cc

@@ -37,6 +37,8 @@ const base::Feature kBraveDomainBlock{"BraveDomainBlock",
 // potentially blocked by Brave Shields.
 const base::Feature kBraveExtensionNetworkBlocking{
     "BraveExtensionNetworkBlocking", base::FEATURE_DISABLED_BY_DEFAULT};
-
+// When enabled, Brave will always report Light in Fingerprinting: Strict mode
+const base::Feature kBraveDarkModeBlock{"BraveDarkModeBlock",
+                                        base::FEATURE_ENABLED_BY_DEFAULT};
 }  // namespace features
 }  // namespace brave_shields

components/brave_shields/common/features.h

@@ -19,6 +19,7 @@ extern const base::Feature kBraveAdblockCosmeticFilteringNative;
 extern const base::Feature kBraveAdblockCspRules;
 extern const base::Feature kBraveDomainBlock;
 extern const base::Feature kBraveExtensionNetworkBlocking;
+extern const base::Feature kBraveDarkModeBlock;
 }  // namespace features
 }  // namespace brave_shields