Remove obsolete includes of SigninManager

Bug: 798411
Change-Id: I67778d6987e52ecd556aba7c90428a7a6f933e00
Reviewed-on: https://chromium-review.googlesource.com/1129230Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574123}

chrome/browser/ui/webui/settings/search_engines_handler.cc

@@ -18,7 +18,6 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/search_engines/ui_thread_search_terms_data.h"
-#include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/search_engines/template_url_table_model.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
@@ -26,7 +25,6 @@
 #include "components/prefs/pref_service.h"
 #include "components/search_engines/template_url.h"
 #include "components/search_engines/template_url_service.h"
-#include "components/signin/core/browser/signin_manager.h"
 #include "content/public/browser/web_ui.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"