Use the DefaultSearchManager as the exclusive authority on DSE, ignoring Web Data.

chrome/browser/search_engines/template_url_service.cc

Index: chrome/browser/search_engines/template_url_service.cc
diff --git a/chrome/browser/search_engines/template_url_service.cc b/chrome/browser/search_engines/template_url_service.cc
index 345786874e08a3ac15f7723b16ddcd43fe7f6c70..aa6938ecdb580bb99f23baae91b00e8823aa6937 100644
--- a/chrome/browser/search_engines/template_url_service.cc
+++ b/chrome/browser/search_engines/template_url_service.cc
@@ -83,20 +83,6 @@ bool TemplateURLMatchesData(const TemplateURL* url1,
           url2->search_terms_replacement_key);
 }
 
-const char kFirstPotentialEngineHistogramName[] =
-    "Search.FirstPotentialEngineCalled";
-
-// Values for an enumerated histogram used to track whenever
-// FirstPotentialDefaultEngine is called, and from where.
-enum FirstPotentialEngineCaller {
-  FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP,
-  FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_PROCESSING_SYNC_CHANGES,
-  FIRST_POTENTIAL_CALLSITE_ON_LOAD,
-  FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_SYNCING,
-  FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_NOT_SYNCING,
-  FIRST_POTENTIAL_CALLSITE_MAX,
-};
-
 const char kDeleteSyncedEngineHistogramName[] =
     "Search.DeleteSyncedSearchEngine";
 
@@ -109,17 +95,6 @@ enum DeleteSyncedSearchEngineEvent {
   DELETE_ENGINE_MAX,
 };
 
-TemplateURL* FirstPotentialDefaultEngine(
-    const TemplateURLService::TemplateURLVector& template_urls) {
-  for (TemplateURLService::TemplateURLVector::const_iterator i(
-       template_urls.begin()); i != template_urls.end(); ++i) {
-    if ((*i)->ShowInDefaultList() &&
-        ((*i)->GetType() == TemplateURL::NORMAL))
-      return *i;
-  }
-  return NULL;
-}
-
 // Returns true iff the change in |change_list| at index |i| should not be sent
 // up to the server based on its GUIDs presence in |sync_data| or when compared
 // to changes after it in |change_list|.
@@ -283,14 +258,14 @@ TemplateURLService::TemplateURLService(Profile* profile)
       load_failed_(false),
       load_handle_(0),
       default_search_provider_(NULL),
-      is_default_search_managed_(false),
       next_id_(kInvalidTemplateURLID + 1),
       time_provider_(&base::Time::Now),
       models_associated_(false),
       processing_syncer_changes_(false),
-      pending_synced_default_search_(false),
-      dsp_change_origin_(DSP_CHANGE_OTHER),
-      default_search_manager_(new DefaultSearchManager(GetPrefs())) {
+      default_search_manager_(new DefaultSearchManager(
+          GetPrefs(),
+          base::Bind(&TemplateURLService::OnDefaultSearchChange,
+                     base::Unretained(this)))) {
   DCHECK(profile_);
   Init(NULL, 0);
 }
@@ -304,13 +279,14 @@ TemplateURLService::TemplateURLService(const Initializer* initializers,
       load_handle_(0),
       service_(NULL),
       default_search_provider_(NULL),
-      is_default_search_managed_(false),
       next_id_(kInvalidTemplateURLID + 1),
       time_provider_(&base::Time::Now),
       models_associated_(false),
       processing_syncer_changes_(false),
-      pending_synced_default_search_(false),
-      dsp_change_origin_(DSP_CHANGE_OTHER) {
+      default_search_manager_(new DefaultSearchManager(
+          GetPrefs(),
+          base::Bind(&TemplateURLService::OnDefaultSearchChange,
+                     base::Unretained(this)))) {
   Init(initializers, count);
 }
 
@@ -530,17 +506,8 @@ void TemplateURLService::AddExtensionControlledTURL(
 
   WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
   if (AddNoNotify(template_url, true)) {
-    // Note that we can't call CanMakeDefault() here, since it would return
-    // false when another extension is already controlling the default search
-    // engine, and we want to allow new extensions to take over.
-    if (template_url->extension_info_->wants_to_be_default_engine &&
-        !is_default_search_managed()) {
-      TemplateURL* default_candidate = FindExtensionDefaultSearchEngine();
-      if (default_candidate == template_url) {
-        base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-            &dsp_change_origin_, DSP_CHANGE_OVERRIDE_SETTINGS_EXTENSION);
-        SetDefaultSearchProviderNoNotify(template_url);
-      }
+    if (template_url->extension_info_->wants_to_be_default_engine) {

[Peter Kasting, 2014/05/03 00:28:18]

Nit: No {}

[erikwright (departed), 2014/05/05 01:49:38]

Done.

+      UpdateExtensionDefaultSearchEngine();
     }
     NotifyObservers();
   }
@@ -558,15 +525,13 @@ void TemplateURLService::RemoveExtensionControlledTURL(
       extension_id, TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION);
   if (!url)
     return;
-  bool restore_dse = (url == GetDefaultSearchProvider());
-  if (restore_dse) {
-    DCHECK(!is_default_search_managed());
-    default_search_provider_ = NULL;
-  }
   WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());

[Peter Kasting, 2014/05/03 00:28:18]

Nit: Leave this just above RemoveNoNotify() where it was before

[erikwright (departed), 2014/05/05 01:49:38]

Done.

+  // NULL this out so that we can call RemoveNoNotify. The subsequent
+  // UpdateExtensionDefaultSearchEngine will cause it to be reset.
+  if (default_search_provider_ == url)
+    default_search_provider_ = NULL;
   RemoveNoNotify(url);
-  if (restore_dse)
-    SetDefaultSearchProviderAfterRemovingDefaultExtension();
+  UpdateExtensionDefaultSearchEngine();
   NotifyObservers();
 }
 
@@ -662,15 +627,14 @@ void TemplateURLService::ResetTemplateURL(TemplateURL* url,
   }
   data.safe_for_autoreplace = false;
   data.last_modified = time_provider_();
-  TemplateURL new_url(url->profile(), data);
+
   UIThreadSearchTermsData search_terms_data(url->profile());
-  if (UpdateNoNotify(url, new_url, search_terms_data))
+  if (UpdateNoNotify(url, data, search_terms_data))
     NotifyObservers();
 }
 
 bool TemplateURLService::CanMakeDefault(const TemplateURL* url) {
-  return  !is_default_search_managed() &&
-      !IsExtensionControlledDefaultSearch() &&
+  return  default_search_provider_source_ <= DefaultSearchManager::FROM_USER &&

[Peter Kasting, 2014/05/03 00:28:18]

Again, I don't like the way this relies on the enum ordering, use explicit ==
and != comparisons instead.

Nit: Extra space; use () around binary subexprs

[erikwright (departed), 2014/05/05 01:49:38]

Done.

       (url != GetDefaultSearchProvider()) &&
       url->url_ref().SupportsReplacement() &&
       (url->GetType() == TemplateURL::NORMAL);
@@ -678,17 +642,20 @@ bool TemplateURLService::CanMakeDefault(const TemplateURL* url) {
 
 void TemplateURLService::SetUserSelectedDefaultSearchProvider(
     TemplateURL* url) {
-  SetDefaultSearchProvider(url);
-  if (default_search_manager_) {
-    if (url)
-      default_search_manager_->SetUserSelectedDefaultSearchEngine(url->data());
-    else
-      default_search_manager_->ClearUserSelectedDefaultSearchEngine();
-  }
+  // Omnibox keywords cannot be made default. Extension-controlled search
+  // engines can be made default only by the extension itself because they
+  // aren't persisted.
+  DCHECK(!url || (url->GetType() == TemplateURL::NORMAL));
+  // We rely on the DefaultSearchManager to push this back to us if, in fact,
+  // the effective DSE changes.
+  if (url)
+    default_search_manager_->SetUserSelectedDefaultSearchEngine(url->data());
+  else
+    default_search_manager_->ClearUserSelectedDefaultSearchEngine();
 }
 
 TemplateURL* TemplateURLService::GetDefaultSearchProvider() {
-  if (loaded_ && !load_failed_)

[Peter Kasting, 2014/05/03 00:28:18]

Making this change causes the behavior of the class to become inconsistent. 
Some functions will refer to |initial_default_search_provider_| when (loaded_ &&
load_failed_), but this one won't.

I think this change is in error unless you want to change everywhere in this
file that refers to load_failed_ or initial_default_search_provider_ to behave
consistently.  It seems like you want to eliminate the idea of "load failed"
entirely, but you haven't done so, and without that you can't make various
changes here and below.

+  if (loaded_)
     return default_search_provider_;
   // We're not loaded, rely on the default search provider stored in prefs.
   return initial_default_search_provider_.get();
@@ -701,43 +668,8 @@ bool TemplateURLService::IsSearchResultsPageFromDefaultSearchProvider(
 }
 
 bool TemplateURLService::IsExtensionControlledDefaultSearch() {
-  const TemplateURL* default_provider = GetDefaultSearchProvider();
-  return default_provider && (default_provider->GetType() ==
-      TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION);
-}
-
-TemplateURL* TemplateURLService::FindNewDefaultSearchProvider() {
-  // See if the prepopulated default still exists.
-  scoped_ptr<TemplateURLData> prepopulated_default =
-      TemplateURLPrepopulateData::GetPrepopulatedDefaultSearch(GetPrefs());
-
-  for (TemplateURLVector::iterator i = template_urls_.begin();
-       i != template_urls_.end(); ++i) {
-    if ((*i)->prepopulate_id() == prepopulated_default->prepopulate_id)
-      return *i;
-  }
-  // If not, use the first non-extension keyword of the templates that supports
-  // search term replacement.
-  if (processing_syncer_changes_) {
-    UMA_HISTOGRAM_ENUMERATION(
-        kFirstPotentialEngineHistogramName,
-        FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_PROCESSING_SYNC_CHANGES,
-        FIRST_POTENTIAL_CALLSITE_MAX);
-  } else {
-    if (sync_processor_.get()) {
-      // We're not currently in a sync cycle, but we're syncing.
-      UMA_HISTOGRAM_ENUMERATION(kFirstPotentialEngineHistogramName,
-                                FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_SYNCING,
-                                FIRST_POTENTIAL_CALLSITE_MAX);
-    } else {
-      // We're not syncing at all.
-      UMA_HISTOGRAM_ENUMERATION(
-          kFirstPotentialEngineHistogramName,
-          FIRST_POTENTIAL_CALLSITE_FIND_NEW_DSP_NOT_SYNCING,
-          FIRST_POTENTIAL_CALLSITE_MAX);
-    }
-  }
-  return FirstPotentialDefaultEngine(template_urls_);
+  return default_search_provider_source_ ==
+         DefaultSearchManager::FROM_EXTENSION;
 }
 
 void TemplateURLService::RepairPrepopulatedSearchEngines() {
@@ -749,11 +681,8 @@ void TemplateURLService::RepairPrepopulatedSearchEngines() {
       TemplateURLPrepopulateData::GetPrepopulatedEngines(
           GetPrefs(), &default_search_provider_index);
   DCHECK(!prepopulated_urls.empty());
-  int default_search_engine_id =
-      prepopulated_urls[default_search_provider_index]->prepopulate_id;
-  TemplateURL* current_dse = default_search_provider_;
   ActionsFromPrepopulateData actions(CreateActionsFromCurrentPrepopulateData(
-      &prepopulated_urls, template_urls_, current_dse));
+      &prepopulated_urls, template_urls_, default_search_provider_));
 
   WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
 
@@ -766,8 +695,7 @@ void TemplateURLService::RepairPrepopulatedSearchEngines() {
   for (EditedEngines::iterator i(actions.edited_engines.begin());
        i < actions.edited_engines.end(); ++i) {
     UIThreadSearchTermsData search_terms_data(profile());
-    TemplateURL new_values(profile(), i->second);
-    UpdateNoNotify(i->first, new_values, search_terms_data);
+    UpdateNoNotify(i->first, i->second, search_terms_data);
   }
 
   // Add items.
@@ -778,15 +706,6 @@ void TemplateURLService::RepairPrepopulatedSearchEngines() {
     AddNoNotify(new TemplateURL(profile_, *i), true);
   }
 
-  // Change the DSE.
-  TemplateURL* new_dse = FindURLByPrepopulateID(template_urls_,
-                                                default_search_engine_id);
-  DCHECK(new_dse);
-  if (CanMakeDefault(new_dse)) {
-    base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-        &dsp_change_origin_, DSP_CHANGE_PROFILE_RESET);
-    SetDefaultSearchProviderNoNotify(new_dse);
-  }
   NotifyObservers();
 }
 
@@ -838,23 +757,27 @@ void TemplateURLService::OnWebDataServiceRequestDone(
     return;
   }
 
-  // initial_default_search_provider_ is only needed before we've finished
-  // loading. Now that we've loaded we can nuke it.
-  initial_default_search_provider_.reset();

[Peter Kasting, 2014/05/03 00:28:18]

Don't eliminate this, just move it lower.  See also comment in
ChangeToLoadedState().  Again, this is part of the inconsistent handling of
"load failed".

-
   TemplateURLVector template_urls;
-  TemplateURL* default_search_provider = NULL;
   int new_resource_keyword_version = 0;
-  GetSearchProvidersUsingKeywordResult(*result, service_.get(), profile_,
-      &template_urls, &default_search_provider, &new_resource_keyword_version,
+  GetSearchProvidersUsingKeywordResult(
+      *result,
+      service_.get(),
+      profile_,
+      &template_urls,
+      default_search_provider_source_ == DefaultSearchManager::FROM_USER
+          ? initial_default_search_provider_.get()

[Peter Kasting, 2014/05/03 00:28:18]

This clang-format output is incorrect; format as:

      (default_search_provider_source_ == DefaultSearchManager::FROM_USER) ?
          initial_default_search_provider_.get() : NULL,

[erikwright (departed), 2014/05/05 01:49:38]

Done.

+          : NULL,
+      &new_resource_keyword_version,
       &pre_sync_deletes_);
 
   WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
 
-  AddTemplateURLsAndSetupDefaultEngine(&template_urls, default_search_provider);
+  PatchMissingSyncGUIDs(&template_urls);
+  SetTemplateURLs(&template_urls);
 
   // This initializes provider_map_ which should be done before
   // calling UpdateKeywordSearchTermsForURL.
+  // This also calls NotifyObservers.

[Peter Kasting, 2014/05/03 00:28:18]

Then should we move up the Notify() call below as well?

[erikwright (departed), 2014/05/05 01:49:38]

Sure. I assume no-one is counting on history to be updated before we say we are
loaded.

   ChangeToLoadedState();
 
   // Index any visits that occurred before we finished loading.
@@ -865,9 +788,6 @@ void TemplateURLService::OnWebDataServiceRequestDone(
   if (new_resource_keyword_version)
     service_->SetBuiltinKeywordVersion(new_resource_keyword_version);
 
-  EnsureDefaultSearchProviderExists();
-
-  NotifyObservers();
   on_loaded_callbacks_.Notify();
 }
 
@@ -896,12 +816,6 @@ void TemplateURLService::Observe(int type,
       visits_to_add_.push_back(*visit_details.ptr());
     else
       UpdateKeywordSearchTermsForURL(*visit_details.ptr());
-  } else if (type == chrome::NOTIFICATION_DEFAULT_SEARCH_POLICY_CHANGED) {
-    // Policy has been updated, so the default search prefs may be different.
-    // Reload the default search provider from them.
-    // TODO(pkasting): Rather than communicating via prefs, we should eventually
-    // observe policy changes directly.
-    UpdateDefaultSearch();
   } else {
     DCHECK_EQ(chrome::NOTIFICATION_GOOGLE_URL_UPDATED, type);
     if (loaded_) {
@@ -922,27 +836,6 @@ void TemplateURLService::Shutdown() {
   service_ = NULL;
 }
 
-void TemplateURLService::OnSyncedDefaultSearchProviderGUIDChanged() {
-  // Listen for changes to the default search from Sync.
-  PrefService* prefs = GetPrefs();
-  TemplateURL* new_default_search = GetTemplateURLForGUID(
-      prefs->GetString(prefs::kSyncedDefaultSearchProviderGUID));
-  if (new_default_search && !is_default_search_managed_) {
-    if (new_default_search != GetDefaultSearchProvider()) {
-      base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-          &dsp_change_origin_, DSP_CHANGE_SYNC_PREF);
-      SetUserSelectedDefaultSearchProvider(new_default_search);
-      pending_synced_default_search_ = false;
-    }
-  } else {
-    // If it's not there, or if default search is currently managed, set a
-    // flag to indicate that we waiting on the search engine entry to come
-    // in through Sync.
-    pending_synced_default_search_ = true;
-  }
-  UpdateDefaultSearch();
-}
-
 syncer::SyncDataList TemplateURLService::GetAllSyncData(
     syncer::ModelType type) const {
   DCHECK_EQ(syncer::SEARCH_ENGINES, type);
@@ -976,12 +869,6 @@ syncer::SyncError TemplateURLService::ProcessSyncChanges(
 
   base::AutoReset<bool> processing_changes(&processing_syncer_changes_, true);
 
-  // We've started syncing, so set our origin member to the base Sync value.
-  // As we move through Sync Code, we may set this to increasingly specific
-  // origins so we can tell what exactly caused a DSP change.
-  base::AutoReset<DefaultSearchChangeOrigin> change_origin(&dsp_change_origin_,
-      DSP_CHANGE_SYNC_UNINTENTIONAL);
-
   WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
 
   syncer::SyncChangeList new_changes;
@@ -1013,34 +900,11 @@ syncer::SyncError TemplateURLService::ProcessSyncChanges(
         continue;
       }
       if (existing_turl == GetDefaultSearchProvider()) {
-        // The only way Sync can attempt to delete the default search provider
-        // is if we had changed the kSyncedDefaultSearchProviderGUID
-        // preference, but perhaps it has not yet been received. To avoid
-        // situations where this has come in erroneously, we will un-delete
-        // the current default search from the Sync data. If the pref really
-        // does arrive later, then default search will change to the correct
-        // entry, but we'll have this extra entry sitting around. The result is
-        // not ideal, but it prevents a far more severe bug where the default is
-        // unexpectedly swapped to something else. The user can safely delete
-        // the extra entry again later, if they choose. Most users who do not
-        // look at the search engines UI will not notice this.
-        // Note that we append a special character to the end of the keyword in
-        // an attempt to avoid a ping-poinging situation where receiving clients
-        // may try to continually delete the resurrected entry.
-        base::string16 updated_keyword = UniquifyKeyword(*existing_turl, true);
-        TemplateURLData data(existing_turl->data());
-        data.SetKeyword(updated_keyword);
-        TemplateURL new_turl(existing_turl->profile(), data);
-        UIThreadSearchTermsData search_terms_data(existing_turl->profile());
-        if (UpdateNoNotify(existing_turl, new_turl, search_terms_data))
-          NotifyObservers();
-
-        syncer::SyncData sync_data = CreateSyncDataFromTemplateURL(new_turl);
-        new_changes.push_back(syncer::SyncChange(FROM_HERE,
-                                                 syncer::SyncChange::ACTION_ADD,
-                                                 sync_data));
-        // Ignore the delete attempt. This means we never end up reseting the
-        // default search provider due to an ACTION_DELETE from sync.
+        // TODO(erikwright): This could happen if the user changes the default
+        // and then deletes the former default. If we receive the keyword sync
+        // before the pref sync we end up here. For now we will just fail to
+        // delete the local record. The user can always correct it later if they
+        // so choose.

[Peter Kasting, 2014/05/03 00:28:18]

Wait, so the user says "delete engine A" and then we don't delete A?  That seems
bad.  Can't we handle this state correctly?

[erikwright (departed), 2014/05/03 00:54:08]

Yes and no.

(1) We could reset the user-selected pref. But that would cause a sync event,
which would potentially override the (not-yet-received) sync event from another
Chrome which contained the user's new choice of DSE.
(2) We could maintain some in-memory state about the pending deletion. But this
would not solve the problem if Chrome exits before the Pref sync is received.
(3) We could add some state to the DB record indicating the pending deletion.
(4) We could add some state to preferences indicating the pending deletion (in a
distinct, unsynced preference).

I suppose (1) would be safe if it was clear that a changed record would override
a deleted record in conflict resolution. I can ask around about that.

(2) Would not be perfect, but would probably significantly reduce the impact of
this issue.

(4) seems acceptable.

Thoughts?

[Peter Kasting, 2014/05/03 01:18:17]

Wait a minute, this code is ACTION_DELETE on the current DSP.  So wouldn't the
right description be "This can happen if the user changes the default in one
client to engine A, then deletes engine A in a separate client"?  I think you
should explicitly ask the sync folks how to handle this.

         continue;
       }
 
@@ -1062,9 +926,6 @@ syncer::SyncError TemplateURLService::ProcessSyncChanges(
       TemplateURLData data(turl->data());
       data.id = kInvalidTemplateURLID;
       Add(new TemplateURL(profile_, data));
-
-      // Possibly set the newly added |turl| as the default search provider.
-      SetDefaultSearchProviderIfNewlySynced(guid);
     } else if (iter->change_type() == syncer::SyncChange::ACTION_UPDATE) {
       if (!existing_turl) {
         error = sync_error_factory_->CreateAndUploadError(
@@ -1079,7 +940,7 @@ syncer::SyncError TemplateURLService::ProcessSyncChanges(
                                    &new_changes);
       }
       UIThreadSearchTermsData search_terms_data(existing_turl->profile());
-      if (UpdateNoNotify(existing_turl, *turl, search_terms_data))
+      if (UpdateNoNotify(existing_turl, turl->data(), search_terms_data))
         NotifyObservers();
     } else {
       // We've unexpectedly received an ACTION_INVALID.
@@ -1113,28 +974,10 @@ syncer::SyncMergeResult TemplateURLService::MergeDataAndStartSyncing(
   sync_processor_ = sync_processor.Pass();
   sync_error_factory_ = sync_error_factory.Pass();
 
-  // We just started syncing, so set our wait-for-default flag if we are
-  // expecting a default from Sync.
-  if (GetPrefs()) {
-    std::string default_guid = GetPrefs()->GetString(
-        prefs::kSyncedDefaultSearchProviderGUID);
-    const TemplateURL* current_default = GetDefaultSearchProvider();
-
-    if (!default_guid.empty() &&
-        (!current_default || current_default->sync_guid() != default_guid))
-      pending_synced_default_search_ = true;
-  }
-
   // We do a lot of calls to Add/Remove/ResetTemplateURL here, so ensure we
   // don't step on our own toes.
   base::AutoReset<bool> processing_changes(&processing_syncer_changes_, true);
 
-  // We've started syncing, so set our origin member to the base Sync value.
-  // As we move through Sync Code, we may set this to increasingly specific
-  // origins so we can tell what exactly caused a DSP change.
-  base::AutoReset<DefaultSearchChangeOrigin> change_origin(&dsp_change_origin_,
-      DSP_CHANGE_SYNC_UNINTENTIONAL);
-
   syncer::SyncChangeList new_changes;
 
   // Build maps of our sync GUIDs to syncer::SyncData.
@@ -1180,7 +1023,7 @@ syncer::SyncMergeResult TemplateURLService::MergeDataAndStartSyncing(
         // also makes the local data's last_modified timestamp equal to Sync's,
         // avoiding an Update on the next MergeData call.
         UIThreadSearchTermsData search_terms_data(local_turl->profile());
-        if (UpdateNoNotify(local_turl, *sync_turl, search_terms_data))
+        if (UpdateNoNotify(local_turl, sync_turl->data(), search_terms_data))
           NotifyObservers();
         merge_result.set_num_items_modified(
             merge_result.num_items_modified() + 1);
@@ -1203,15 +1046,6 @@ syncer::SyncMergeResult TemplateURLService::MergeDataAndStartSyncing(
     }
   }
 
-  // If there is a pending synced default search provider that was processed
-  // above, set it now.
-  TemplateURL* pending_default = GetPendingSyncedDefaultSearchProvider();
-  if (pending_default) {
-    base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-        &dsp_change_origin_, DSP_CHANGE_SYNC_ADD);
-    SetUserSelectedDefaultSearchProvider(pending_default);
-  }
-
   // The remaining SyncData in local_data_map should be everything that needs to
   // be pushed as ADDs to sync.
   for (SyncDataMap::const_iterator iter = local_data_map.begin();
@@ -1456,16 +1290,12 @@ void TemplateURLService::Init(const Initializer* initializers,
                                 profile_source);
     notification_registrar_.Add(this, chrome::NOTIFICATION_GOOGLE_URL_UPDATED,
                                 profile_source);
-    pref_change_registrar_.Init(GetPrefs());
-    pref_change_registrar_.Add(
-        prefs::kSyncedDefaultSearchProviderGUID,
-        base::Bind(
-            &TemplateURLService::OnSyncedDefaultSearchProviderGUIDChanged,
-            base::Unretained(this)));
   }
-  notification_registrar_.Add(
-      this, chrome::NOTIFICATION_DEFAULT_SEARCH_POLICY_CHANGED,
-      content::NotificationService::AllSources());
+
+  DefaultSearchManager::Source source = DefaultSearchManager::FROM_USER;
+  TemplateURLData* dse =
+      default_search_manager_->GetDefaultSearchEngine(&source);
+  OnDefaultSearchChange(dse, source);
 
   if (num_initializers > 0) {
     // This path is only hit by test code and is used to simulate a loaded
@@ -1490,17 +1320,15 @@ void TemplateURLService::Init(const Initializer* initializers,
 
       // Set the first provided identifier to be the default.
       if (i == 0)
-        SetDefaultSearchProviderNoNotify(template_url);
+        default_search_manager_->SetUserSelectedDefaultSearchEngine(data);
     }
   }
 
-  // Initialize default search.
-  UpdateDefaultSearch();
-
   // Request a server check for the correct Google URL if Google is the
   // default search engine and not in headless mode.
-  if (profile_ && initial_default_search_provider_.get() &&
-      initial_default_search_provider_->url_ref().HasGoogleBaseURLs()) {
+  TemplateURL* default_search_provider = GetDefaultSearchProvider();
+  if (profile_ && default_search_provider &&
+      default_search_provider->url_ref().HasGoogleBaseURLs()) {
     scoped_ptr<base::Environment> env(base::Environment::Create());
     if (!env->HasVar(env_vars::kHeadless))
       GoogleURLTracker::RequestServerCheck(profile_, false);
@@ -1613,11 +1441,18 @@ void TemplateURLService::ChangeToLoadedState() {
   UIThreadSearchTermsData search_terms_data(profile_);
   provider_map_->Init(template_urls_, search_terms_data);
   loaded_ = true;
+
+  // This will cause a call to NotifyObservers().
+  OnDefaultSearchChange(initial_default_search_provider_
+                            ? &initial_default_search_provider_->data()
+                            : NULL,

[Peter Kasting, 2014/05/03 00:28:18]

Again, format as

  OnDefaultSearchChange(
      initial_default_search_provider_ ?
          initial_default_search_provider_->data() : NULL,
      default_search_provider_source_);

[erikwright (departed), 2014/05/05 01:49:38]

Done.

+                        default_search_provider_source_);
+  initial_default_search_provider_.reset();

[Peter Kasting, 2014/05/03 00:28:18]

You can't reset this here, unless you completely eliminate the idea of
|load_failed_|.

[erikwright (departed), 2014/05/05 01:49:38]

Oops, I had meant to.

 }
 
-void TemplateURLService::SaveDefaultSearchProviderToPrefs(
-    const TemplateURL* t_url) {
-  PrefService* prefs = GetPrefs();
+// static
+void TemplateURLService::SaveDefaultSearchProviderToLegacyPrefs(
+    const TemplateURL* t_url, PrefService* prefs) {

[Peter Kasting, 2014/05/03 00:28:18]

Nit: One arg per line

[erikwright (departed), 2014/05/05 01:49:38]

Done.

   if (!prefs)
     return;
 
@@ -1688,10 +1523,11 @@ void TemplateURLService::SaveDefaultSearchProviderToPrefs(
       search_terms_replacement_key);
 }
 
-bool TemplateURLService::LoadDefaultSearchProviderFromPrefs(
+// static
+bool TemplateURLService::LoadDefaultSearchProviderFromLegacyPrefs(
+    PrefService* prefs,
     scoped_ptr<TemplateURLData>* default_provider_data,
     bool* is_managed) {
-  PrefService* prefs = GetPrefs();
   if (!prefs || !prefs->HasPrefPath(prefs::kDefaultSearchProviderSearchURL) ||
       !prefs->HasPrefPath(prefs::kDefaultSearchProviderKeyword))
     return false;
@@ -1784,16 +1620,6 @@ bool TemplateURLService::LoadDefaultSearchProviderFromPrefs(
   return true;
 }
 
-void TemplateURLService::ClearDefaultProviderFromPrefs() {
-  // We overwrite user preferences. If the default search engine is managed,
-  // there is no effect.
-  SaveDefaultSearchProviderToPrefs(NULL);
-  // Default value for kDefaultSearchProviderEnabled is true.
-  PrefService* prefs = GetPrefs();
-  if (prefs)
-    prefs->SetBoolean(prefs::kDefaultSearchProviderEnabled, true);
-}
-
 bool TemplateURLService::CanReplaceKeywordForHost(
     const std::string& host,
     TemplateURL** to_replace) {
@@ -1834,7 +1660,7 @@ TemplateURL* TemplateURLService::FindNonExtensionTemplateURLForKeyword(
 
 bool TemplateURLService::UpdateNoNotify(
     TemplateURL* existing_turl,
-    const TemplateURL& new_values,
+    const TemplateURLData& new_values,
     const SearchTermsData& old_search_terms_data) {
   DCHECK(loaded_);
   DCHECK(existing_turl);
@@ -1892,9 +1718,10 @@ bool TemplateURLService::UpdateNoNotify(
                            existing_turl,
                            syncer::SyncChange::ACTION_UPDATE);
 
-  if (default_search_provider_ == existing_turl) {
-    bool success = SetDefaultSearchProviderNoNotify(existing_turl);
-    DCHECK(success);
+  if (default_search_provider_ == existing_turl &&
+      default_search_provider_source_ == DefaultSearchManager::FROM_USER) {
+    default_search_manager_->SetUserSelectedDefaultSearchEngine(
+        default_search_provider_->data());
   }
   return true;
 }
@@ -1915,7 +1742,7 @@ void TemplateURLService::UpdateTemplateURLIfPrepopulated(
   for (size_t i = 0; i < prepopulated_urls.size(); ++i) {
     if (prepopulated_urls[i]->prepopulate_id == prepopulate_id) {
       MergeIntoPrepopulatedEngineData(template_url, prepopulated_urls[i]);
-      template_url->CopyFrom(TemplateURL(profile, *prepopulated_urls[i]));
+      template_url->CopyFrom(*prepopulated_urls[i]);
     }
   }
 }
@@ -2010,7 +1837,7 @@ void TemplateURLService::GoogleBaseURLChanged(const GURL& old_base_url) {
       // This will send the keyword change to sync.  Note that other clients
       // need to reset the keyword to an appropriate local value when this
       // change arrives; see CreateTemplateURLFromTemplateURLAndSyncData().
-      UpdateNoNotify(t_url, updated_turl,
+      UpdateNoNotify(t_url, updated_turl.data(),
           OldBaseURLSearchTermsData(t_url->profile(), old_base_url.spec()));
     }
   }
@@ -2018,205 +1845,103 @@ void TemplateURLService::GoogleBaseURLChanged(const GURL& old_base_url) {
     NotifyObservers();
 }
 
-void TemplateURLService::UpdateDefaultSearch() {
+void TemplateURLService::OnDefaultSearchChange(
+    const TemplateURLData* data,
+    DefaultSearchManager::Source source) {
   if (!loaded_) {
-    // Set |initial_default_search_provider_| from the preferences.  We use this
-    // value for default search provider until the database has been loaded.
-    scoped_ptr<TemplateURLData> data;
-    if (!LoadDefaultSearchProviderFromPrefs(&data,
-                                            &is_default_search_managed_)) {
-      // Prefs does not specify, so rely on the prepopulated engines.  This
-      // should happen only the first time Chrome is started.
-      data =
-          TemplateURLPrepopulateData::GetPrepopulatedDefaultSearch(GetPrefs());
-      is_default_search_managed_ = false;
-    }
-
+    // Set |initial_default_search_provider_| from the preferences. This is
+    // mainly so we can hold ownership until we get to the point where the list
+    // of keywords from Web Data is the owner of everything including the
+    // default.
     initial_default_search_provider_.reset(
         data ? new TemplateURL(profile_, *data) : NULL);
+    default_search_provider_source_ = source;
+    return;
+  }
 
+  // Prevent recursion if we update the value stored in default_search_manager_.
+  // Note that we exclude if data == NULL because that could cause a false
+  // positive for recursion when the initial_default_search_provider_ is NULL
+  // due to policy. No recursion case could lead to recursion with NULL.
+  if (source == default_search_provider_source_ && data != NULL &&
+      TemplateURLMatchesData(default_search_provider_, data))
     return;
+
+  WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
+  if (default_search_provider_source_ == DefaultSearchManager::FROM_POLICY ||
+      source == DefaultSearchManager::FROM_POLICY) {
+    // We do this both to clear up removed policy-defined DSE as well as to add
+    // the new one, if appropriate.
+    UpdateProvidersCreatedByPolicy(
+        &template_urls_,
+        source == DefaultSearchManager::FROM_POLICY ? data : NULL);
   }
-  // Load the default search specified in prefs.
-  scoped_ptr<TemplateURLData> new_default_from_prefs;
-  bool new_is_default_managed = false;
-  // Load the default from prefs.  It's possible that it won't succeed
-  // because we are in the middle of doing SaveDefaultSearchProviderToPrefs()
-  // and all the preference items have not been saved.  In that case, we
-  // don't have yet a default.  It would be much better if we could save
-  // preferences in batches and trigger notifications at the end.
-  LoadDefaultSearchProviderFromPrefs(&new_default_from_prefs,
-                                     &new_is_default_managed);
-  if (!is_default_search_managed_ && !new_is_default_managed) {
-    // We're not interested in cases where the default was and remains
-    // unmanaged.  In that case, preferences have no impact on the default.
+
+  if (!data) {
+    default_search_provider_ = NULL;
+    default_search_provider_source_ = source;
+    NotifyObservers();
     return;
   }
-  WebDataService::KeywordBatchModeScoper keyword_scoper(service_.get());
-  if (is_default_search_managed_ && new_is_default_managed) {
-    // The default was managed and remains managed.  Update the default only
-    // if it has changed; we don't want to respond to changes triggered by
-    // SaveDefaultSearchProviderToPrefs.
-    if (TemplateURLMatchesData(default_search_provider_,
-                               new_default_from_prefs.get()))
-      return;
-    if (!new_default_from_prefs) {
-      // default_search_provider_ can't be NULL otherwise
-      // TemplateURLMatchesData would have returned true.  Remove this now
-      // invalid value.
-      TemplateURL* old_default = default_search_provider_;
-      bool success = SetDefaultSearchProviderNoNotify(NULL);
-      DCHECK(success);
-      RemoveNoNotify(old_default);
-    } else if (default_search_provider_) {
-      new_default_from_prefs->created_by_policy = true;
-      TemplateURL new_values(profile_, *new_default_from_prefs);
+
+  if (source == DefaultSearchManager::FROM_EXTENSION) {
+    default_search_provider_ = FindMatchingExtensionTemplateURL(
+        *data, TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION);
+  }
+
+  if (source == DefaultSearchManager::FROM_FALLBACK) {
+    default_search_provider_ =
+        FindPrepopulatedTemplateURL(data->prepopulate_id);
+    if (default_search_provider_) {
+      TemplateURLData update_data(*data);
+      update_data.sync_guid = default_search_provider_->sync_guid();
       UIThreadSearchTermsData search_terms_data(
           default_search_provider_->profile());
-      UpdateNoNotify(default_search_provider_, new_values, search_terms_data);
+      UpdateNoNotify(default_search_provider_, update_data, search_terms_data);
     } else {
-      TemplateURL* new_template = NULL;
-      if (new_default_from_prefs) {
-        new_default_from_prefs->created_by_policy = true;
-        new_template = new TemplateURL(profile_, *new_default_from_prefs);
-        if (!AddNoNotify(new_template, true))
-          return;
-      }
-      bool success = SetDefaultSearchProviderNoNotify(new_template);
-      DCHECK(success);
-    }
-  } else if (!is_default_search_managed_ && new_is_default_managed) {
-    // The default used to be unmanaged and is now managed.  Add the new
-    // managed default to the list of URLs and set it as default.
-    is_default_search_managed_ = new_is_default_managed;
-    TemplateURL* new_template = NULL;
-    if (new_default_from_prefs) {
-      new_default_from_prefs->created_by_policy = true;
-      new_template = new TemplateURL(profile_, *new_default_from_prefs);
-      if (!AddNoNotify(new_template, true))
-        return;
+      // TODO(erikwright): AFAIU something ought to have inserted all of the
+      // pre-populated DSEs in web data by now.. Maybe it isn't done in tests^
+      TemplateURL* new_dse = new TemplateURL(profile_, *data);
+      if (AddNoNotify(new_dse, true))
+        default_search_provider_ = new_dse;
+      else
+        delete new_dse;
     }
-    bool success = SetDefaultSearchProviderNoNotify(new_template);
-    DCHECK(success);
-  } else {
-    // The default was managed and is no longer.
-    DCHECK(is_default_search_managed_ && !new_is_default_managed);
-    is_default_search_managed_ = new_is_default_managed;
-    // If we had a default, delete the previous default if created by policy
-    // and set a likely default.
-    if ((default_search_provider_ != NULL) &&
-        default_search_provider_->created_by_policy()) {
-      TemplateURL* old_default = default_search_provider_;
-      default_search_provider_ = NULL;
-      RemoveNoNotify(old_default);
-    }
-
-    // The likely default should be from Sync if we were waiting on Sync.
-    // Otherwise, it should be FindNewDefaultSearchProvider.
-    TemplateURL* synced_default = GetPendingSyncedDefaultSearchProvider();
-    if (synced_default) {
-      pending_synced_default_search_ = false;
-
-      base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-          &dsp_change_origin_, DSP_CHANGE_SYNC_NOT_MANAGED);
-      SetDefaultSearchProviderNoNotify(synced_default);
+  }
+  if (source == DefaultSearchManager::FROM_USER) {
+    default_search_provider_ = GetTemplateURLForGUID(data->sync_guid);
+    if (default_search_provider_) {
+      TemplateURLData new_data(*data);
+      new_data.show_in_default_list = true;
+      UIThreadSearchTermsData search_terms_data(
+          default_search_provider_->profile());
+      UpdateNoNotify(default_search_provider_, new_data, search_terms_data);
     } else {
-      SetDefaultSearchProviderNoNotify(FindNewDefaultSearchProvider());
+      TemplateURL* new_dse = new TemplateURL(profile_, *data);
+      new_dse->data_.show_in_default_list = true;
+      new_dse->data_.id = kInvalidTemplateURLID;
+      if (!AddNoNotify(new_dse, true))
+        delete new_dse;
+      else
+        default_search_provider_ = new_dse;
     }
-  }
-  NotifyObservers();
-}
 
-void TemplateURLService::SetDefaultSearchProvider(
-    TemplateURL* url) {
-  DCHECK(!is_default_search_managed_);
-  // Omnibox keywords cannot be made default. Extension-controlled search
-  // engines can be made default only by the extension itself because they
-  // aren't persisted.
-  DCHECK(!url || (url->GetType() == TemplateURL::NORMAL));
-
-  // Always persist the setting in the database, that way if the backup
-  // signature has changed out from under us it gets reset correctly.
-  if (SetDefaultSearchProviderNoNotify(url))
-    NotifyObservers();
-}
-
-bool TemplateURLService::SetDefaultSearchProviderNoNotify(TemplateURL* url) {
-  if (url) {
-    if (std::find(template_urls_.begin(), template_urls_.end(), url) ==
-        template_urls_.end())
-      return false;
-    // Omnibox keywords cannot be made default.
-    DCHECK_NE(TemplateURL::OMNIBOX_API_EXTENSION, url->GetType());
-  }
-
-  // Only bother reassigning |url| if it has changed. Notice that we don't just
-  // early exit if they are equal, because |url| may have had its fields
-  // changed, and needs to be persisted below (for example, when this is called
-  // from UpdateNoNotify).
-  if (default_search_provider_ != url) {
-    // Engines set by policy override extension-controlled engines, which
-    // override other engines.
-    DCHECK(!is_default_search_managed() || !url ||
-           (url->GetType() == TemplateURL::NORMAL));
-    if (is_default_search_managed() || !default_search_provider_ ||
-        (default_search_provider_->GetType() == TemplateURL::NORMAL) ||
-        (url &&
-         (url->GetType() == TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION))){
-      UMA_HISTOGRAM_ENUMERATION("Search.DefaultSearchChangeOrigin",
-                                dsp_change_origin_, DSP_CHANGE_MAX);
-      default_search_provider_ = url;
-    }
   }
 
-  if (url) {
-    // Don't mark the url as edited, otherwise we won't be able to rev the
-    // template urls we ship with.
-    url->data_.show_in_default_list = true;
-    if (service_.get() && (url->GetType() == TemplateURL::NORMAL))
-      service_->UpdateKeyword(url->data());
+  default_search_provider_source_ = source;
 
-    if (url->url_ref().HasGoogleBaseURLs()) {
+  if (default_search_provider_ &&
+      default_search_provider_->url_ref().HasGoogleBaseURLs()) {
+    if (profile_)
       GoogleURLTracker::RequestServerCheck(profile_, false);
 #if defined(ENABLE_RLZ)
-      RLZTracker::RecordProductEvent(rlz_lib::CHROME,
-                                     RLZTracker::CHROME_OMNIBOX,
-                                     rlz_lib::SET_TO_GOOGLE);
+    // TODO(erikwright): should this only be if user-selected?
+    RLZTracker::RecordProductEvent(
+        rlz_lib::CHROME, RLZTracker::CHROME_OMNIBOX, rlz_lib::SET_TO_GOOGLE);
 #endif
-    }
-  }
-
-  // Extension-controlled search engines shouldn't be persisted anywhere.
-  if (url && (url->GetType() == TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION))
-    return true;
-
-  if (!is_default_search_managed_) {
-    SaveDefaultSearchProviderToPrefs(url);
-
-    // If we are syncing, we want to set the synced pref that will notify other
-    // instances to change their default to this new search provider.
-    // Note: we don't update the pref if we're currently in the middle of
-    // handling a sync operation. Sync operations from other clients are not
-    // guaranteed to arrive together, and any client that deletes the default
-    // needs to set a new default as well. If we update the default here, we're
-    // likely to race with the update from the other client, resulting in
-    // a possibly random default search provider.
-    if (sync_processor_.get() && url && !url->sync_guid().empty() &&
-        GetPrefs() && !processing_syncer_changes_) {
-      GetPrefs()->SetString(prefs::kSyncedDefaultSearchProviderGUID,
-                            url->sync_guid());
-    }
   }
 
-  if (service_.get())
-    service_->SetDefaultSearchProviderID(url ? url->id() : 0);
-
-  // Inform sync the change to the show_in_default_list flag.
-  if (url)
-    ProcessTemplateURLChange(FROM_HERE,
-                             url,
-                             syncer::SyncChange::ACTION_UPDATE);
-  return true;
+  NotifyObservers();
 }
 
 bool TemplateURLService::AddNoNotify(TemplateURL* template_url,
@@ -2321,41 +2046,35 @@ void TemplateURLService::NotifyObservers() {
 }
 
 // |template_urls| are the TemplateURLs loaded from the database.
-// |default_search_provider| points to one of them, if it was set in the db.
-// |default_from_prefs| is the default search provider from the preferences.
-// Check |is_default_search_managed_| to determine if it was set by policy.
+// |default_from_prefs| is the default search provider from the preferences, or
+// NULL if the DSE is not policy-defined.
 //
 // This function removes from the vector and the database all the TemplateURLs
-// that were set by policy, unless it is the current default search provider
-// and matches what is set by a managed preference.
-void TemplateURLService::RemoveProvidersCreatedByPolicy(
+// that were set by policy, unless it is the current default search provider, in
+// which case it is updated with the data from prefs.
+void TemplateURLService::UpdateProvidersCreatedByPolicy(
     TemplateURLVector* template_urls,
-    TemplateURL** default_search_provider,
-    TemplateURLData* default_from_prefs) {
+    const TemplateURLData* default_from_prefs) {
   DCHECK(template_urls);
-  DCHECK(default_search_provider);
+
   for (TemplateURLVector::iterator i = template_urls->begin();
        i != template_urls->end(); ) {
     TemplateURL* template_url = *i;
     if (template_url->created_by_policy()) {
-      if (template_url == *default_search_provider &&
-          is_default_search_managed_ &&
+      if (default_from_prefs &&
           TemplateURLMatchesData(template_url, default_from_prefs)) {
         // If the database specified a default search provider that was set
         // by policy, and the default search provider from the preferences
         // is also set by policy and they are the same, keep the entry in the
         // database and the |default_search_provider|.
+        default_search_provider_ = template_url;
+        // Prevent us from saving any other entries, or creating a new one.
+        default_from_prefs = NULL;
         ++i;
         continue;
       }
 
-      // The database loaded a managed |default_search_provider|, but it has
-      // been updated in the prefs. Remove it from the database, and update the
-      // |default_search_provider| pointer here.
-      if (*default_search_provider &&
-          (*default_search_provider)->id() == template_url->id())
-        *default_search_provider = NULL;
-
+      RemoveFromMaps(template_url);
       i = template_urls->erase(i);
       if (service_.get())
         service_->RemoveKeyword(template_url->id());
@@ -2364,6 +2083,18 @@ void TemplateURLService::RemoveProvidersCreatedByPolicy(
       ++i;
     }
   }
+
+  if (default_from_prefs) {
+    default_search_provider_ = NULL;
+    default_search_provider_source_ = DefaultSearchManager::FROM_POLICY;
+    TemplateURLData new_data(*default_from_prefs);
+    new_data.created_by_policy = true;
+    TemplateURL* new_dse = new TemplateURL(profile_, new_data);
+    if (!AddNoNotify(new_dse, true))
+      delete new_dse;
+    else
+      default_search_provider_ = new_dse;
+  }
 }
 
 void TemplateURLService::ResetTemplateURLGUID(TemplateURL* url,
@@ -2373,9 +2104,8 @@ void TemplateURLService::ResetTemplateURLGUID(TemplateURL* url,
 
   TemplateURLData data(url->data());
   data.sync_guid = guid;
-  TemplateURL new_url(url->profile(), data);
   UIThreadSearchTermsData search_terms_data(url->profile());
-  UpdateNoNotify(url, new_url, search_terms_data);
+  UpdateNoNotify(url, data, search_terms_data);
 }
 
 base::string16 TemplateURLService::UniquifyKeyword(const TemplateURL& turl,
@@ -2446,9 +2176,8 @@ void TemplateURLService::ResolveSyncKeywordConflict(
     // Update |applied_sync_turl| in the local model with the new keyword.
     TemplateURLData data(applied_sync_turl->data());
     data.SetKeyword(new_keyword);
-    TemplateURL new_turl(applied_sync_turl->profile(), data);
     UIThreadSearchTermsData search_terms_data(applied_sync_turl->profile());
-    if (UpdateNoNotify(applied_sync_turl, new_turl, search_terms_data))
+    if (UpdateNoNotify(applied_sync_turl, data, search_terms_data))
       NotifyObservers();
   }
   // The losing TemplateURL should have their keyword updated. Send a change to
@@ -2497,18 +2226,6 @@ void TemplateURLService::MergeInSyncTemplateURL(
             CreateSyncDataFromTemplateURL(*conflicting_turl);
         change_list->push_back(syncer::SyncChange(
             FROM_HERE, syncer::SyncChange::ACTION_UPDATE, sync_data));
-        if (conflicting_turl == GetDefaultSearchProvider() &&
-            !pending_synced_default_search_) {
-          // If we're not waiting for the Synced default to come in, we should
-          // override the pref with our new GUID. If we are waiting for the
-          // arrival of a synced default, setting the pref here would cause us
-          // to lose the GUID we are waiting on.
-          PrefService* prefs = GetPrefs();
-          if (prefs) {
-            prefs->SetString(prefs::kSyncedDefaultSearchProviderGUID,
-                             conflicting_turl->sync_guid());
-          }
-        }
         // Note that in this case we do not add the Sync TemplateURL to the
         // local model, since we've effectively "merged" it in by updating the
         // local conflicting entry with its sync_guid.
@@ -2539,37 +2256,6 @@ void TemplateURLService::MergeInSyncTemplateURL(
   }
 }
 
-void TemplateURLService::SetDefaultSearchProviderIfNewlySynced(
-    const std::string& guid) {
-  // If we're not syncing or if default search is managed by policy, ignore.
-  if (!sync_processor_.get() || is_default_search_managed_)
-    return;
-
-  PrefService* prefs = GetPrefs();
-  if (prefs && pending_synced_default_search_ &&
-      prefs->GetString(prefs::kSyncedDefaultSearchProviderGUID) == guid) {
-    // Make sure this actually exists. We should not be calling this unless we
-    // really just added this TemplateURL.
-    TemplateURL* turl_from_sync = GetTemplateURLForGUID(guid);
-    if (turl_from_sync && turl_from_sync->SupportsReplacement()) {
-      base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-          &dsp_change_origin_, DSP_CHANGE_SYNC_ADD);
-      SetDefaultSearchProvider(turl_from_sync);
-    }
-    pending_synced_default_search_ = false;
-  }
-}
-
-TemplateURL* TemplateURLService::GetPendingSyncedDefaultSearchProvider() {
-  PrefService* prefs = GetPrefs();
-  if (!prefs || !pending_synced_default_search_)
-    return NULL;
-
-  // Could be NULL if no such thing exists.
-  return GetTemplateURLForGUID(
-      prefs->GetString(prefs::kSyncedDefaultSearchProviderGUID));
-}
-
 void TemplateURLService::PatchMissingSyncGUIDs(
     TemplateURLVector* template_urls) {
   DCHECK(template_urls);
@@ -2587,112 +2273,15 @@ void TemplateURLService::PatchMissingSyncGUIDs(
   }
 }
 
-void TemplateURLService::AddTemplateURLsAndSetupDefaultEngine(
-    TemplateURLVector* template_urls,
-    TemplateURL* default_search_provider) {
-  DCHECK(template_urls);
-  is_default_search_managed_ = false;
-  bool database_specified_a_default = (default_search_provider != NULL);
-
-  // Check if default search provider is now managed.
-  scoped_ptr<TemplateURLData> default_from_prefs;
-  LoadDefaultSearchProviderFromPrefs(&default_from_prefs,
-                                     &is_default_search_managed_);
-
-  // Remove entries that were created because of policy as they may have
-  // changed since the database was saved.
-  RemoveProvidersCreatedByPolicy(template_urls,
-                                 &default_search_provider,
-                                 default_from_prefs.get());
-
-  PatchMissingSyncGUIDs(template_urls);
-
-  if (is_default_search_managed_) {
-    SetTemplateURLs(template_urls);
-
-    if (TemplateURLMatchesData(default_search_provider,
-                               default_from_prefs.get())) {
-      // The value from the preferences was previously stored in the database.
-      // Reuse it.
-    } else {
-      // The value from the preferences takes over.
-      default_search_provider = NULL;
-      if (default_from_prefs) {
-        default_from_prefs->created_by_policy = true;
-        default_from_prefs->id = kInvalidTemplateURLID;
-        default_search_provider =
-            new TemplateURL(profile_, *default_from_prefs);
-        if (!AddNoNotify(default_search_provider, true))
-          default_search_provider = NULL;
-      }
-    }
-    // Note that this saves the default search provider to prefs.
-    if (!default_search_provider ||
-        ((default_search_provider->GetType() !=
-            TemplateURL::OMNIBOX_API_EXTENSION) &&
-         default_search_provider->SupportsReplacement())) {
-      bool success = SetDefaultSearchProviderNoNotify(default_search_provider);
-      DCHECK(success);
-    }
-  } else {
-    // If we had a managed default, replace it with the synced default if
-    // applicable, or the first provider of the list.
-    TemplateURL* synced_default = GetPendingSyncedDefaultSearchProvider();
-    if (synced_default) {
-      default_search_provider = synced_default;
-      pending_synced_default_search_ = false;
-    } else if (database_specified_a_default &&
-        default_search_provider == NULL) {
-      UMA_HISTOGRAM_ENUMERATION(kFirstPotentialEngineHistogramName,
-                                FIRST_POTENTIAL_CALLSITE_ON_LOAD,
-                                FIRST_POTENTIAL_CALLSITE_MAX);
-      default_search_provider = FirstPotentialDefaultEngine(*template_urls);
-    }
-
-    // If the default search provider existed previously, then just
-    // set the member variable. Otherwise, we'll set it using the method
-    // to ensure that it is saved properly after its id is set.
-    if (default_search_provider &&
-        (default_search_provider->id() != kInvalidTemplateURLID)) {
-      default_search_provider_ = default_search_provider;
-      default_search_provider = NULL;
-    }
-    SetTemplateURLs(template_urls);
-
-    if (default_search_provider) {
-      base::AutoReset<DefaultSearchChangeOrigin> change_origin(
-          &dsp_change_origin_, default_from_prefs ?
-              dsp_change_origin_ : DSP_CHANGE_NEW_ENGINE_NO_PREFS);
-      // Note that this saves the default search provider to prefs.
-      SetDefaultSearchProvider(default_search_provider);
-    } else {
-      // Always save the default search provider to prefs. That way we don't
-      // have to worry about it being out of sync.
-      if (default_search_provider_)
-        SaveDefaultSearchProviderToPrefs(default_search_provider_);
-    }
+TemplateURL* TemplateURLService::FindPrepopulatedTemplateURL(
+    int prepopulated_id) const {
+  for (TemplateURLVector::const_iterator i = template_urls_.begin();
+       i != template_urls_.end(); ++i) {
+    if ((*i)->prepopulate_id() == prepopulated_id)
+      return *i;
   }
-}
 
-void TemplateURLService::EnsureDefaultSearchProviderExists() {
-  if (!is_default_search_managed()) {
-    bool has_default_search_provider = default_search_provider_ &&
-        default_search_provider_->SupportsReplacement();
-    UMA_HISTOGRAM_BOOLEAN("Search.HasDefaultSearchProvider",
-                          has_default_search_provider);
-    // Ensure that default search provider exists. See http://crbug.com/116952.
-    if (!has_default_search_provider) {
-      bool success =
-          SetDefaultSearchProviderNoNotify(FindNewDefaultSearchProvider());
-      DCHECK(success);
-    }
-    // Don't log anything if the user has a NULL default search provider.
-    if (default_search_provider_) {
-      UMA_HISTOGRAM_ENUMERATION("Search.DefaultSearchProviderType",
-          TemplateURLPrepopulateData::GetEngineType(*default_search_provider_),
-          SEARCH_ENGINE_MAX);
-    }
-  }
+  return NULL;
 }
 
 TemplateURL* TemplateURLService::CreateTemplateURLForExtension(
@@ -2721,7 +2310,20 @@ TemplateURL* TemplateURLService::FindTemplateURLForExtension(
   return NULL;
 }
 
-TemplateURL* TemplateURLService::FindExtensionDefaultSearchEngine() const {
+TemplateURL* TemplateURLService::FindMatchingExtensionTemplateURL(
+    const TemplateURLData& data,
+    TemplateURL::Type type) const {
+  DCHECK_NE(TemplateURL::NORMAL, type);
+  for (TemplateURLVector::const_iterator i = template_urls_.begin();
+       i != template_urls_.end(); ++i) {
+    if ((*i)->GetType() == type && TemplateURLMatchesData(*i, &data))
+      return *i;
+  }
+
+  return NULL;
+}
+
+void TemplateURLService::UpdateExtensionDefaultSearchEngine() {
   TemplateURL* most_recently_intalled_default = NULL;
   for (TemplateURLVector::const_iterator i = template_urls_.begin();
        i != template_urls_.end(); ++i) {
@@ -2734,28 +2336,10 @@ TemplateURL* TemplateURLService::FindExtensionDefaultSearchEngine() const {
       most_recently_intalled_default = *i;
   }
 
-  return most_recently_intalled_default;
-}
-
-void TemplateURLService::
-    SetDefaultSearchProviderAfterRemovingDefaultExtension() {
-  DCHECK(!is_default_search_managed());
-  TemplateURL* new_dse = FindExtensionDefaultSearchEngine();
-  if (!new_dse) {
-    scoped_ptr<TemplateURLData> default_provider;
-    bool is_managed;
-    if (LoadDefaultSearchProviderFromPrefs(&default_provider, &is_managed) &&
-        default_provider) {
-      for (TemplateURLVector::const_iterator i = template_urls_.begin();
-           i != template_urls_.end(); ++i) {
-        if ((*i)->id() == default_provider->id) {
-          new_dse = *i;
-          break;
-        }
-      }
-    }
+  if (most_recently_intalled_default) {
+    default_search_manager_->SetExtensionControlledDefaultSearchEngine(
+        new TemplateURLData(most_recently_intalled_default->data()));
+  } else {
+    default_search_manager_->ClearExtensionControlledDefaultSearchEngine();
   }
-  if (!new_dse)
-    new_dse = FindNewDefaultSearchProvider();
-  SetDefaultSearchProviderNoNotify(new_dse);
 }