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

chrome/browser/search_engines/search_provider_install_data.cc

 // Copyright (c) 2012 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 "chrome/browser/search_engines/search_provider_install_data.h"
 
 #include <algorithm>
 #include <functional>
 #include <vector>
 
@@ skipping 231 matching lines @@
   // the destructor.
   load_handle_ = 0;
 
   if (!result) {
     // Results are null if the database went away or (most likely) wasn't
     // loaded.
     OnLoadFailed();
     return;
   }
 
-  TemplateURL* default_search_provider = NULL;
   int new_resource_keyword_version = 0;
   std::vector<TemplateURL*> extracted_template_urls;
-  GetSearchProvidersUsingKeywordResult(*result, NULL, NULL,
-      &extracted_template_urls, &default_search_provider,
-      &new_resource_keyword_version, NULL);
+  GetSearchProvidersUsingKeywordResult(*result,
+                                       NULL,
+                                       NULL,
+                                       &extracted_template_urls,
+                                       NULL,
+                                       &new_resource_keyword_version,
+                                       NULL);
   template_urls_.get().insert(template_urls_.get().begin(),
                               extracted_template_urls.begin(),
                               extracted_template_urls.end());
   IOThreadSearchTermsData search_terms_data(google_base_url_);
   provider_map_.reset(new SearchHostToURLsMap());
   provider_map_->Init(template_urls_.get(), search_terms_data);
-  SetDefault(default_search_provider);
+  // TODO(erikwright): This needs to be based on prefs now...
+  SetDefault(NULL);

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

Um, what is the effect of not getting this right today?  "SetDefault(NULL)"
worries me that you're going to break something important.

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

I intend to resolve this TODO before committing.

   NotifyLoaded();
 }
 
 void SearchProviderInstallData::SetDefault(const TemplateURL* template_url) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   if (!template_url) {
     default_search_origin_.clear();
     return;
   }
@@ skipping 28 matching lines @@
 
   std::for_each(closure_queue.begin(),
                 closure_queue.end(),
                 std::mem_fun_ref(&base::Closure::Run));
 
   // Since we expect this request to be rare, clear out the information. This
   // also keeps the responses current as the search providers change.
   provider_map_.reset();
   SetDefault(NULL);
 }