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

This is a reland of 66d17ca7

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}

Change-Id: Ie4c6c3767af38efe50e42012aa5f65fb480fac56
Reviewed-on: https://chromium-review.googlesource.com/1099976Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567242}

chrome/browser/conflicts/incompatible_applications_updater_win.cc

@@ -8,14 +8,18 @@
 #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"
@@ -223,8 +227,11 @@ void IncompatibleApplicationsUpdater::RegisterLocalStatePrefs(
 
 // static
 bool IncompatibleApplicationsUpdater::IsWarningEnabled() {
-  return ModuleDatabase::GetInstance() &&
-         ModuleDatabase::GetInstance()->third_party_conflicts_manager();
+  return base::win::GetVersion() >= base::win::VERSION_WIN10 &&
+         base::FeatureList::IsEnabled(features::kModuleDatabase) &&
+         ModuleDatabase::IsThirdPartyBlockingPolicyEnabled() &&
+         base::FeatureList::IsEnabled(
+             features::kIncompatibleApplicationsWarning);
 }
 
 // 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. The
-  // return value will not change throughout the lifetime of the process.
+  // Returns true if the tracking of incompatible applications is enabled. Note
+  // that this is a Windows 10+ feature only.
   static bool IsWarningEnabled();
 
   // Returns true if the cache contains at least one incompatible application.

chrome/browser/conflicts/module_database_win.cc

@@ -10,7 +10,6 @@
 #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)
@@ -288,10 +287,12 @@ void ModuleDatabase::NotifyLoadedModules(ModuleDatabaseObserver* observer) {
 
 #if defined(GOOGLE_CHROME_BUILD)
 void ModuleDatabase::MaybeInitializeThirdPartyConflictsManager() {
-  if (base::win::GetVersion() >= base::win::VERSION_WIN10 &&
-      IsThirdPartyBlockingPolicyEnabled() &&
-      base::FeatureList::IsEnabled(
-          features::kIncompatibleApplicationsWarning)) {
+  if (!IsThirdPartyBlockingPolicyEnabled())
+    return;
+
+  if (base::FeatureList::IsEnabled(
+          features::kIncompatibleApplicationsWarning) ||
+      base::FeatureList::IsEnabled(features::kThirdPartyModulesBlocking)) {
     third_party_conflicts_manager_ =
         std::make_unique<ThirdPartyConflictsManager>(this);
     AddObserver(third_party_conflicts_manager_.get());

chrome/browser/conflicts/module_database_win.h

@@ -118,13 +118,14 @@ class ModuleDatabase {
 #if defined(GOOGLE_CHROME_BUILD)
   static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);
 
-  // Returns true if the ThirdPartyBlocking policy is enabled. This can only
-  // return false if it is disabled via admin policy.
+  // Returns false if third-party modules blocking is disabled via
+  // administrative 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 the tracking of incompatible applications is disabled.
+  // Returns null if both the tracking of incompatible applications and the
+  // blocking of third-party modules are disabled.
   ThirdPartyConflictsManager* third_party_conflicts_manager() {
     return third_party_conflicts_manager_.get();
   }
@@ -178,12 +179,11 @@ class ModuleDatabase {
   void NotifyLoadedModules(ModuleDatabaseObserver* observer);
 
 #if defined(GOOGLE_CHROME_BUILD)
-  // 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.
+  // 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.
   void MaybeInitializeThirdPartyConflictsManager();
 
   void OnThirdPartyBlockingPolicyChanged();

chrome/browser/conflicts/third_party_blocking_browsertest.cc

@@ -13,7 +13,6 @@
 #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"
@@ -159,9 +158,6 @@ 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());
@@ -203,5 +199,5 @@ IN_PROC_BROWSER_TEST_F(ThirdPartyBlockingBrowserTest,
             ReadModuleBlacklistCache(module_blacklist_cache_path, &metadata,
                                      &blacklisted_modules, &md5_digest));
 
-  EXPECT_EQ(1u, blacklisted_modules.size());
+  EXPECT_GE(blacklisted_modules.size(), 1);
 }