Disable Real Time lookup policy

It seems there's some confusion about exactly how the policy should behave,
so disable it for M79 while we clarify the semantics.

Bug: 1015484
Change-Id: I21f62e06277ec34bc64c611324234fdf8e5949be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1867089Reviewed-by: Bettina Dea <bdea@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707073}

chrome/browser/policy/policy_browsertest.cc

@@ -5743,7 +5743,9 @@ IN_PROC_BROWSER_TEST_F(PolicyTestWithRealTimeUrlLookupFetchAllowList,
             std::make_unique<base::Value>(true));
   UpdateProviderPolicy(policies);
 
-  EXPECT_TRUE(safe_browsing::RealTimePolicyEngine::CanPerformFullURLLookup(
+  // TODO(crbug.com/1015484): This should be enabled, once we clarify the
+  // policy semantics.
+  EXPECT_FALSE(safe_browsing::RealTimePolicyEngine::CanPerformFullURLLookup(
       browser()->profile()));
 }
 

components/safe_browsing/realtime/policy_engine.cc

@@ -36,8 +36,9 @@ bool RealTimePolicyEngine::IsUserOptedIn(
 // static
 bool RealTimePolicyEngine::IsEnabledByPolicy(
     content::BrowserContext* browser_context) {
-  PrefService* pref_service = user_prefs::UserPrefs::Get(browser_context);
-  return pref_service->GetBoolean(prefs::kSafeBrowsingRealTimeLookupEnabled);
+  // TODO(crbug.com/1015484): Once the policy semantics are understood, check if
+  // they are enabled here.
+  return false;
 }
 
 // static

components/safe_browsing/realtime/policy_engine_unittest.cc

@@ -51,7 +51,9 @@ TEST_F(RealTimePolicyEngineTest, TestCanPerformFullURLLookup_EnabledByPolicy) {
   feature_list.InitAndEnableFeature(kRealTimeUrlLookupFetchAllowlist);
   pref_service_.SetUserPref(prefs::kSafeBrowsingRealTimeLookupEnabled,
                             std::make_unique<base::Value>(true));
-  EXPECT_TRUE(CanPerformFullURLLookup());
+  // TODO(crbug.com/1015484): This should be enabled, once we clarify the policy
+  // semantics.
+  EXPECT_FALSE(CanPerformFullURLLookup());
 }
 
 TEST_F(RealTimePolicyEngineTest,