Cleanup parameter passing issues in content/browser/download

content/browser/download/download_manager_impl.cc

 // Copyright (c) 2011 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 "content/browser/download/download_manager_impl.h"
 
 #include <iterator>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 406 matching lines @@
                  download_path));
 
   download->Rename(download_path);
 
   delegate_->AddItemToPersistentStore(download);
 }
 
 void DownloadManagerImpl::UpdateDownload(int32 download_id,
                                          int64 bytes_so_far,
                                          int64 bytes_per_sec,
-                                         std::string hash_state) {
+                                         const std::string& hash_state) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DownloadMap::iterator it = active_downloads_.find(download_id);
   if (it != active_downloads_.end()) {
     DownloadItem* download = it->second;
     if (download->IsInProgress()) {
       download->UpdateProgress(bytes_so_far, bytes_per_sec, hash_state);
       UpdateDownloadProgress();  // Reflect size updates.
       delegate_->UpdateItemInPersistentStore(download);
     }
   }
@@ skipping 178 matching lines @@
   // This function is called from the DownloadItem, so DI state
   // should already have been updated.
   AssertStateConsistent(download);
 
   if (file_manager_)
     download->OffThreadCancel(file_manager_);
 }
 
 void DownloadManagerImpl::OnDownloadInterrupted(int32 download_id,
                                                 int64 size,
-                                                std::string hash_state,
+                                                const std::string& hash_state,
                                                 InterruptReason reason) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   DownloadItem* download = GetActiveDownload(download_id);
   if (!download)
     return;
 
   VLOG(20) << __FUNCTION__ << "()"
            << " reason " << InterruptReasonDebugString(reason)
            << " at offset " << download->GetReceivedBytes()
@@ skipping 499 matching lines @@
        it != history_downloads_.end(); ++it) {
     if (it->second->IsComplete() && !it->second->GetOpened())
       ++num_unopened;
   }
   download_stats::RecordOpensOutstanding(num_unopened);
 }
 
 void DownloadManagerImpl::SetFileManager(DownloadFileManager* file_manager) {
   file_manager_ = file_manager;
 }