Fixes clear cookies on exit toggle.

Fixes brave/brave-browser#6119

Account for CONTENT_SETTING_SESSION_ONLY as a possibility for the
default cookie setting in preferences - do not override it with
CONTENT_SETTING_ALLOW if it's already set.

Added browser test CookiePrefServiceTest.CookieControlType_Preference to
test Shields cookie setting change when preference setting changes
and in reverse.

components/brave_shields/browser/cookie_pref_service.cc

@@ -46,8 +46,12 @@ void SetCookiePrefDefaults(HostContentSettingsMap* map, PrefService* prefs) {
     prefs->SetInteger("profile.default_content_setting_values.cookies",
                       CONTENT_SETTING_BLOCK);
   } else {
-    prefs->SetInteger("profile.default_content_setting_values.cookies",
-                      CONTENT_SETTING_ALLOW);
+    int value =
+        prefs->GetInteger("profile.default_content_setting_values.cookies");
+    if (IntToContentSetting(value) != CONTENT_SETTING_SESSION_ONLY) {
+      value = CONTENT_SETTING_ALLOW;
+    }
+    prefs->SetInteger("profile.default_content_setting_values.cookies", value);
   }
 }
 

components/brave_shields/browser/cookie_pref_service_browsertest.cc

@@ -0,0 +1,78 @@
+/* Copyright (c) 2019 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/brave_shields/browser/brave_shields_util.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "components/content_settings/core/common/content_settings.h"
+#include "components/prefs/pref_service.h"
+#include "url/gurl.h"
+
+using brave_shields::ControlType;
+
+class CookiePrefServiceTest : public InProcessBrowserTest {
+ public:
+  CookiePrefServiceTest() = default;
+  ~CookiePrefServiceTest() override = default;
+
+  Profile* profile() { return browser()->profile(); }
+
+  ContentSetting GetCookiePref() {
+    return IntToContentSetting(profile()->GetPrefs()->GetInteger(
+        "profile.default_content_setting_values.cookies"));
+  }
+
+  void SetCookiePref(ContentSetting setting) {
+    profile()->GetPrefs()->SetInteger(
+        "profile.default_content_setting_values.cookies", setting);
+  }
+};
+
+IN_PROC_BROWSER_TEST_F(CookiePrefServiceTest, CookieControlType_Preference) {
+  // Initial state
+  auto setting = brave_shields::GetCookieControlType(profile(), GURL());
+  EXPECT_EQ(ControlType::BLOCK_THIRD_PARTY, setting);
+  EXPECT_EQ(CONTENT_SETTING_ALLOW, GetCookiePref());
+
+  // Control -> preference
+  /* BLOCK */
+  brave_shields::SetCookieControlType(profile(), ControlType::BLOCK, GURL());
+  EXPECT_EQ(CONTENT_SETTING_BLOCK, GetCookiePref());
+
+  /* ALLOW */
+  brave_shields::SetCookieControlType(profile(), ControlType::ALLOW, GURL());
+  EXPECT_EQ(CONTENT_SETTING_ALLOW, GetCookiePref());
+
+  /* BLOCK_THIRD_PARTY */
+  brave_shields::SetCookieControlType(profile(), ControlType::BLOCK, GURL());
+  EXPECT_EQ(CONTENT_SETTING_BLOCK, GetCookiePref());
+  brave_shields::SetCookieControlType(profile(), ControlType::BLOCK_THIRD_PARTY,
+                                      GURL());
+  EXPECT_EQ(CONTENT_SETTING_ALLOW, GetCookiePref());
+
+  // Preference -> control
+  /* BLOCK */
+  SetCookiePref(CONTENT_SETTING_BLOCK);
+  EXPECT_EQ(ControlType::BLOCK,
+            brave_shields::GetCookieControlType(profile(), GURL()));
+
+  /* ALLOW */
+  SetCookiePref(CONTENT_SETTING_ALLOW);
+  EXPECT_EQ(ControlType::ALLOW,
+            brave_shields::GetCookieControlType(profile(), GURL()));
+
+  // Preserve CONTENT_SETTING_SESSION_ONLY
+  SetCookiePref(CONTENT_SETTING_BLOCK);
+  EXPECT_EQ(ControlType::BLOCK,
+            brave_shields::GetCookieControlType(profile(), GURL()));
+  SetCookiePref(CONTENT_SETTING_SESSION_ONLY);
+  EXPECT_EQ(ControlType::ALLOW,
+            brave_shields::GetCookieControlType(profile(), GURL()));
+  SetCookiePref(CONTENT_SETTING_ALLOW);
+  EXPECT_EQ(ControlType::ALLOW,
+            brave_shields::GetCookieControlType(profile(), GURL()));
+}

test/BUILD.gn

@@ -501,6 +501,7 @@ test("brave_browser_tests") {
     "//brave/chromium_src/third_party/blink/renderer/modules/bluetooth/navigator_bluetoothtest.cc",
     "//brave/common/brave_channel_info_browsertest.cc",
     "//brave/components/brave_shields/browser/ad_block_service_browsertest.cc",
+    "//brave/components/brave_shields/browser/cookie_pref_service_browsertest.cc",
     "//brave/components/brave_shields/browser/https_everywhere_service_browsertest.cc",
     "//brave/components/brave_shields/browser/referrer_whitelist_service_browsertest.cc",
     "//brave/components/brave_shields/browser/tracking_protection_service_browsertest.cc",