Remove legacy popular sites cache cleaning

components/ntp_tiles/popular_sites_impl.h

Index: components/ntp_tiles/popular_sites_impl.h
diff --git a/components/ntp_tiles/popular_sites_impl.h b/components/ntp_tiles/popular_sites_impl.h
index b045dea6a7994c0adc70e21de9283115b6a7600c..116297342df9466729f7474f2572684cca59922c 100644
--- a/components/ntp_tiles/popular_sites_impl.h
+++ b/components/ntp_tiles/popular_sites_impl.h
@@ -10,7 +10,6 @@
 #include <vector>
 
 #include "base/callback.h"
-#include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string16.h"
@@ -19,8 +18,6 @@
 #include "url/gurl.h"
 
 namespace base {
-class TaskRunner;
-class SequencedWorkerPool;
 class Value;
 }
 
@@ -51,12 +48,10 @@ using ParseJSONCallback = base::Callback<void(
 class PopularSitesImpl : public PopularSites, public net::URLFetcherDelegate {
  public:
   PopularSitesImpl(
-      const scoped_refptr<base::SequencedWorkerPool>& blocking_pool,
       PrefService* prefs,
       const TemplateURLService* template_url_service,
       variations::VariationsService* variations_service,
       net::URLRequestContextGetter* download_context,
-      const base::FilePath& directory,
       ParseJSONCallback parse_json);
 
   ~PopularSitesImpl() override;
@@ -89,7 +84,6 @@ class PopularSitesImpl : public PopularSites, public net::URLFetcherDelegate {
   void OnDownloadFailed();
 
   // Parameters set from constructor.
-  scoped_refptr<base::TaskRunner> const blocking_runner_;
   PrefService* const prefs_;
   const TemplateURLService* const template_url_service_;
   variations::VariationsService* const variations_;