Remove StricterMixedContentTreatmentEnabled policy

This policy was meant to be temporary (initially planned to be removed
in M84). This CL removes it.

components/page_info and weblayer/test were missing a direct dependency on components/prefs,
which were previously resolved through the dependency on security_state,
this also adds those dependency directly to their build files.

Bug: 1093820
Change-Id: Id1f903e9de2bec54e68bc68acb54cc789e11839b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2242750
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: Emily Stark <[email protected]>
Reviewed-by: Mark Cogan <[email protected]>
Reviewed-by: Tim Volodine <[email protected]>
Reviewed-by: Martin Šrámek <[email protected]>
Reviewed-by: Julian Pastarmov <[email protected]>
Reviewed-by: Christopher Thompson <[email protected]>
Commit-Queue: Carlos IL <[email protected]>
Cr-Commit-Position: refs/heads/master@{#779505}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index e7159953..c844293 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -137,7 +137,6 @@
 #include "components/safe_browsing/core/common/safe_browsing_prefs.h"
 #include "components/search_engines/template_url_prepopulate_data.h"
 #include "components/security_interstitials/content/stateful_ssl_host_state_delegate.h"
-#include "components/security_state/core/security_state.h"
 #include "components/sessions/core/session_id_generator.h"
 #include "components/signin/public/identity_manager/identity_manager.h"
 #include "components/subresource_filter/content/browser/ruleset_service.h"
@@ -549,6 +548,10 @@
 const char kSupervisedUsersNextId[] = "LocallyManagedUsersNextId";
 #endif  // defined(OS_CHROMEOS)
 
+// Deprecated 6/2020
+const char kStricterMixedContentTreatmentEnabled[] =
+    "security_state.stricter_mixed_content_treatment_enabled";
+
 // Register local state used only for migration (clearing or moving to a new
 // key).
 void RegisterLocalStatePrefsForMigration(PrefRegistrySimple* registry) {
@@ -650,6 +653,8 @@
   registry->RegisterDictionaryPref(kPreviewsLPRHostBlacklist);
   registry->RegisterDictionaryPref(kPreviewsLPRProbeCache);
   registry->RegisterDictionaryPref(kPreviewsLPROriginProbeCache);
+
+  registry->RegisterBooleanPref(kStricterMixedContentTreatmentEnabled, true);
 }
 
 }  // namespace
@@ -901,7 +906,6 @@
   safe_browsing::RegisterProfilePrefs(registry);
   blocked_content::SafeBrowsingTriggeredPopupBlocker::RegisterProfilePrefs(
       registry);
-  security_state::RegisterProfilePrefs(registry);
   SessionStartupPref::RegisterProfilePrefs(registry);
   SharingSyncPreference::RegisterProfilePrefs(registry);
   sync_sessions::SessionSyncPrefs::RegisterProfilePrefs(registry);
@@ -1289,4 +1293,7 @@
   profile_prefs->ClearPref(kPreviewsLPRHostBlacklist);
   profile_prefs->ClearPref(kPreviewsLPRProbeCache);
   profile_prefs->ClearPref(kPreviewsLPROriginProbeCache);
+
+  // Added 6/2020
+  profile_prefs->ClearPref(kStricterMixedContentTreatmentEnabled);
 }