Revert of Make extensions DSE persistent in browser prefs

components/search_engines/default_search_manager.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/search_engines/default_search_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/i18n/case_conversion.h"
 #include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_service.h"
 #include "components/prefs/pref_value_map.h"
 #include "components/search_engines/search_engines_pref_names.h"
 #include "components/search_engines/template_url_data.h"
 #include "components/search_engines/template_url_data_util.h"
@@ skipping 104 matching lines @@
   if (extension_default_search_) {
     if (source)
       *source = FROM_EXTENSION;
     return extension_default_search_.get();
   }
   if (prefs_default_search_) {
     if (source)
       *source = FROM_USER;
     return prefs_default_search_.get();
   }
+
   if (source)
     *source = FROM_FALLBACK;
   return g_fallback_search_engines_disabled ?
       NULL : fallback_default_search_.get();
 }
 
 DefaultSearchManager::Source
 DefaultSearchManager::GetDefaultSearchEngineSource() const {
   Source source;
   GetDefaultSearchEngine(&source);
   return source;
 }
 
 void DefaultSearchManager::SetUserSelectedDefaultSearchEngine(
     const TemplateURLData& data) {
   if (!pref_service_) {
     prefs_default_search_.reset(new TemplateURLData(data));
     MergePrefsDataWithPrepopulated();
     NotifyObserver();
     return;
   }
 
   pref_service_->Set(kDefaultSearchProviderDataPrefName,
                      *TemplateURLDataToDictionary(data));
 }
 
+void DefaultSearchManager::SetExtensionControlledDefaultSearchEngine(
+    const TemplateURLData& data) {
+  extension_default_search_.reset(new TemplateURLData(data));
+  if (GetDefaultSearchEngineSource() == FROM_EXTENSION)
+    NotifyObserver();
+}
+
+void DefaultSearchManager::ClearExtensionControlledDefaultSearchEngine() {
+  Source old_source = GetDefaultSearchEngineSource();
+  extension_default_search_.reset();
+  if (old_source == FROM_EXTENSION)
+    NotifyObserver();
+}
+
 void DefaultSearchManager::ClearUserSelectedDefaultSearchEngine() {
   if (pref_service_) {
     pref_service_->ClearPref(kDefaultSearchProviderDataPrefName);
   } else {
     prefs_default_search_.reset();
     NotifyObserver();
   }
 }
 
 void DefaultSearchManager::OnDefaultSearchPrefChanged() {
-  bool source_was_fallback = GetDefaultSearchEngineSource() == FROM_FALLBACK;
-
+  Source source = GetDefaultSearchEngineSource();
   LoadDefaultSearchEngineFromPrefs();
 
-  // The effective DSE may have changed unless we were using the fallback source
-  // both before and after the above load.
-  if (!source_was_fallback || (GetDefaultSearchEngineSource() != FROM_FALLBACK))
+  // If we were/are FROM_USER or FROM_POLICY the effective DSE may have changed.
+  if (source != FROM_USER && source != FROM_POLICY)
+    source = GetDefaultSearchEngineSource();
+  if (source == FROM_USER || source == FROM_POLICY)
     NotifyObserver();
 }
 
 void DefaultSearchManager::OnOverridesPrefChanged() {
   LoadPrepopulatedDefaultSearch();
 
   TemplateURLData* effective_data = GetDefaultSearchEngine(NULL);
   if (effective_data && effective_data->prepopulate_id) {
     // A user-selected, policy-selected or fallback pre-populated engine is
     // active and may have changed with this event.
@@ skipping 28 matching lines @@
     prefs_default_search_ = std::move(engine);
     return;
   }
 }
 
 void DefaultSearchManager::LoadDefaultSearchEngineFromPrefs() {
   if (!pref_service_)
     return;
 
   prefs_default_search_.reset();
-  extension_default_search_.reset();
   const PrefService::Preference* pref =
       pref_service_->FindPreference(kDefaultSearchProviderDataPrefName);
   DCHECK(pref);
   default_search_controlled_by_policy_ = pref->IsManaged();
 
   const base::DictionaryValue* url_dict =
       pref_service_->GetDictionary(kDefaultSearchProviderDataPrefName);
   if (url_dict->empty())
     return;
 
   if (default_search_controlled_by_policy_) {
     bool disabled_by_policy = false;
     if (url_dict->GetBoolean(kDisabledByPolicy, &disabled_by_policy) &&
         disabled_by_policy)
       return;
   }
 
   auto turl_data = TemplateURLDataFromDictionary(*url_dict);
   if (!turl_data)
     return;
 
-  // Check if default search preference is overriden by extension.
-  if (pref->IsExtensionControlled()) {
-    extension_default_search_ = std::move(turl_data);
-  } else {
-    prefs_default_search_ = std::move(turl_data);
-    MergePrefsDataWithPrepopulated();
-  }
+  prefs_default_search_ = std::move(turl_data);
+  MergePrefsDataWithPrepopulated();
 }
 
 void DefaultSearchManager::LoadPrepopulatedDefaultSearch() {
   std::unique_ptr<TemplateURLData> data =
       TemplateURLPrepopulateData::GetPrepopulatedDefaultSearch(pref_service_);
   fallback_default_search_ = std::move(data);
   MergePrefsDataWithPrepopulated();
 }
 
 void DefaultSearchManager::NotifyObserver() {
   if (!change_observer_.is_null()) {
     Source source = FROM_FALLBACK;
     TemplateURLData* data = GetDefaultSearchEngine(&source);
     change_observer_.Run(data, source);
   }
 }