Popular sites on the NTP: re-download popular suggestions once per Chrome run

chrome/browser/net/file_downloader.cc

 // Copyright 2015 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/net/file_downloader.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
 using net::URLFetcher;
 
 const int kNumRetries = 1;
 
 FileDownloader::FileDownloader(const GURL& url,
                                const base::FilePath& path,
+                               bool overwrite,
                                net::URLRequestContextGetter* request_context,
                                const DownloadFinishedCallback& callback)
     : callback_(callback),
       fetcher_(URLFetcher::Create(url, URLFetcher::GET, this)),
       weak_ptr_factory_(this) {
   fetcher_->SetRequestContext(request_context);
   fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                          net::LOAD_DO_NOT_SAVE_COOKIES);
   fetcher_->SetAutomaticallyRetryOnNetworkChanges(kNumRetries);
   fetcher_->SaveResponseToFileAtPath(
       path,
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
 
-  base::PostTaskAndReplyWithResult(
-      BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
-          base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN).get(),
-      FROM_HERE,
-      base::Bind(&base::PathExists, path),
-      base::Bind(&FileDownloader::OnFileExistsCheckDone,
-                 weak_ptr_factory_.GetWeakPtr()));
+  if (overwrite) {
+    fetcher_->Start();
+  } else {
+    base::PostTaskAndReplyWithResult(
+        BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
+            base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN).get(),
+        FROM_HERE,
+        base::Bind(&base::PathExists, path),
+        base::Bind(&FileDownloader::OnFileExistsCheckDone,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
 }
 
 FileDownloader::~FileDownloader() {}
 
 void FileDownloader::OnURLFetchComplete(const net::URLFetcher* source) {
   DCHECK_EQ(fetcher_.get(), source);
   // Delete |fetcher_| when we leave this method. This is necessary so the
   // download file will be deleted if the download failed.
   scoped_ptr<net::URLFetcher> fetcher(fetcher_.Pass());
 
   const net::URLRequestStatus& status = source->GetStatus();
   if (!status.is_success()) {
-    DLOG(WARNING) << "URLRequestStatus error " << status.error();
+    DLOG(WARNING) << "URLRequestStatus error " << status.error()
+        << " while trying to download " << source->GetURL().spec();
     callback_.Run(false);
     return;
   }
 
   int response_code = source->GetResponseCode();
   if (response_code != net::HTTP_OK) {
-    DLOG(WARNING) << "HTTP error " << response_code;
+    DLOG(WARNING) << "HTTP error " << response_code
+        << " while trying to download " << source->GetURL().spec();
     callback_.Run(false);
     return;
   }
 
   // Take ownership of the new file.
   base::FilePath response_path;
   bool success = source->GetResponseAsFilePath(true, &response_path);
   callback_.Run(success);
 }
 
 void FileDownloader::OnFileExistsCheckDone(bool exists) {
   if (exists)
     callback_.Run(true);
   else
     fetcher_->Start();
 }