Revert "Make the ThirdPartyModulesBlocking feature work on all Windows versions"

This reverts commit 66d17ca7.

Reason for revert: This test fails in official builds:
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/86110

Original change's description:
> Make the ThirdPartyModulesBlocking feature work on all Windows versions
> 
> Change-Id: I0118d26fe9b7f11f2608dd66c10418e210393733
> Reviewed-on: https://chromium-review.googlesource.com/1083842
> Commit-Queue: Patrick Monette <pmonette@chromium.org>
> Reviewed-by: Greg Thompson <grt@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#566516}

TBR=pmonette@chromium.org,grt@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: Ide1a33af76247dd31b82aa3d49916fe2ec1859a4
Reviewed-on: https://chromium-review.googlesource.com/1099698Reviewed-by: Reid Kleckner <rnk@chromium.org>
Commit-Queue: Reid Kleckner <rnk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566996}

chrome/browser/conflicts/incompatible_applications_updater_win.cc

@@ -8,18 +8,14 @@
 #include <utility>
 
 #include "base/bind.h"
-#include "base/feature_list.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "base/win/registry.h"
-#include "base/win/windows_version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/conflicts/module_database_win.h"
 #include "chrome/browser/conflicts/module_info_util_win.h"
-#include "chrome/browser/conflicts/module_info_win.h"
 #include "chrome/browser/conflicts/module_list_filter_win.h"
 #include "chrome/browser/conflicts/third_party_metrics_recorder_win.h"
-#include "chrome/common/chrome_features.h"
 #include "chrome/common/pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
@@ -227,11 +223,8 @@ void IncompatibleApplicationsUpdater::RegisterLocalStatePrefs(
 
 // static
 bool IncompatibleApplicationsUpdater::IsWarningEnabled() {
-  return base::win::GetVersion() >= base::win::VERSION_WIN10 &&
-         base::FeatureList::IsEnabled(features::kModuleDatabase) &&
-         ModuleDatabase::IsThirdPartyBlockingPolicyEnabled() &&
-         base::FeatureList::IsEnabled(
-             features::kIncompatibleApplicationsWarning);
+  return ModuleDatabase::GetInstance() &&
+         ModuleDatabase::GetInstance()->third_party_conflicts_manager();
 }
 
 // static

chrome/browser/conflicts/incompatible_applications_updater_win.h

@@ -49,8 +49,8 @@ class IncompatibleApplicationsUpdater : public ModuleDatabaseObserver {
 
   static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);
 
-  // Returns true if the tracking of incompatible applications is enabled. Note
-  // that this is a Windows 10+ feature only.
+  // Returns true if the tracking of incompatible applications is enabled. The
+  // return value will not change throughout the lifetime of the process.
   static bool IsWarningEnabled();
 
   // Returns true if the cache contains at least one incompatible application.

chrome/browser/conflicts/module_database_win.cc

@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
+#include "base/win/windows_version.h"
 #include "chrome/browser/conflicts/module_database_observer_win.h"
 
 #if defined(GOOGLE_CHROME_BUILD)
@@ -287,12 +288,10 @@ void ModuleDatabase::NotifyLoadedModules(ModuleDatabaseObserver* observer) {
 
 #if defined(GOOGLE_CHROME_BUILD)
 void ModuleDatabase::MaybeInitializeThirdPartyConflictsManager() {
-  if (!IsThirdPartyBlockingPolicyEnabled())
-    return;
-
-  if (base::FeatureList::IsEnabled(
-          features::kIncompatibleApplicationsWarning) ||
-      base::FeatureList::IsEnabled(features::kThirdPartyModulesBlocking)) {
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10 &&
+      IsThirdPartyBlockingPolicyEnabled() &&
+      base::FeatureList::IsEnabled(
+          features::kIncompatibleApplicationsWarning)) {
     third_party_conflicts_manager_ =
         std::make_unique<ThirdPartyConflictsManager>(this);
     AddObserver(third_party_conflicts_manager_.get());

chrome/browser/conflicts/module_database_win.h

@@ -118,14 +118,13 @@ class ModuleDatabase {
 #if defined(GOOGLE_CHROME_BUILD)
   static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);
 
-  // Returns false if third-party modules blocking is disabled via
-  // administrative policy.
+  // Returns true if the ThirdPartyBlocking policy is enabled. This can only
+  // return false if it is disabled via admin policy.
   static bool IsThirdPartyBlockingPolicyEnabled();
 
   // Accessor for the third party conflicts manager. This is exposed so that the
   // manager can be wired up to the ThirdPartyModuleListComponentInstaller.
-  // Returns null if both the tracking of incompatible applications and the
-  // blocking of third-party modules are disabled.
+  // Returns null if the tracking of incompatible applications is disabled.
   ThirdPartyConflictsManager* third_party_conflicts_manager() {
     return third_party_conflicts_manager_.get();
   }
@@ -179,11 +178,12 @@ class ModuleDatabase {
   void NotifyLoadedModules(ModuleDatabaseObserver* observer);
 
 #if defined(GOOGLE_CHROME_BUILD)
-  // Initializes the ThirdPartyConflictsManager, which controls showing warnings
-  // for incompatible applications that inject into Chrome and the blocking of
-  // third-party modules. The manager is only initialized if either or both of
-  // the ThirdPartyModulesBlocking and IncompatibleApplicationsWarning features
-  // are enabled.
+  // Initializes the ThirdPartyConflictsManager, which controls the warning of
+  // incompatible applications that injects into Chrome and the blocking of
+  // third-party modules.
+  // The manager is not initialized if it is disabled via a base::Feature or a
+  // group policy. Note that it is also not initialized on Windows version
+  // 8.1 and less.
   void MaybeInitializeThirdPartyConflictsManager();
 
   void OnThirdPartyBlockingPolicyChanged();

chrome/browser/conflicts/third_party_blocking_browsertest.cc

@@ -13,6 +13,7 @@
 #include "base/scoped_native_library.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/test/test_reg_util_win.h"
+#include "base/win/windows_version.h"
 #include "chrome/browser/conflicts/incompatible_applications_updater_win.h"
 #include "chrome/browser/conflicts/module_blacklist_cache_updater_win.h"
 #include "chrome/browser/conflicts/module_blacklist_cache_util_win.h"
@@ -158,6 +159,9 @@ class ThirdPartyBlockingBrowserTest : public InProcessBrowserTest {
 //       browser launch.
 IN_PROC_BROWSER_TEST_F(ThirdPartyBlockingBrowserTest,
                        CreateModuleBlacklistCache) {
+  if (base::win::GetVersion() < base::win::VERSION_WIN10)
+    return;
+
   base::FilePath module_list_path;
   ASSERT_NO_FATAL_FAILURE(CreateModuleList(&module_list_path));
   ASSERT_FALSE(module_list_path.empty());