[Downloads] Rework how hashes are calculated for download files.

content/browser/download/download_manager_impl.cc

Index: content/browser/download/download_manager_impl.cc
diff --git a/content/browser/download/download_manager_impl.cc b/content/browser/download/download_manager_impl.cc
index 3fcb33ef51edfe4b895112a7ce292e14f8af65c4..a7d66d2cb9593cfa1b1212de2802a8ee2511c46d 100644
--- a/content/browser/download/download_manager_impl.cc
+++ b/content/browser/download/download_manager_impl.cc
@@ -119,31 +119,17 @@ class DownloadItemFactoryImpl : public DownloadItemFactory {
       const std::string& last_modified,
       int64_t received_bytes,
       int64_t total_bytes,
+      const std::string& hash,
       DownloadItem::DownloadState state,
       DownloadDangerType danger_type,
       DownloadInterruptReason interrupt_reason,
       bool opened,
       const net::BoundNetLog& bound_net_log) override {
     return new DownloadItemImpl(
-        delegate,
-        download_id,
-        current_path,
-        target_path,
-        url_chain,
-        referrer_url,
-        mime_type,
-        original_mime_type,
-        start_time,
-        end_time,
-        etag,
-        last_modified,
-        received_bytes,
-        total_bytes,
-        state,
-        danger_type,
-        interrupt_reason,
-        opened,
-        bound_net_log);
+        delegate, download_id, current_path, target_path, url_chain,
+        referrer_url, mime_type, original_mime_type, start_time, end_time, etag,
+        last_modified, received_bytes, total_bytes, hash, state, danger_type,
+        interrupt_reason, opened, bound_net_log);
   }
 
   DownloadItemImpl* CreateActiveItem(
@@ -362,16 +348,13 @@ void DownloadManagerImpl::StartDownloadWithId(
   if (info->result == DOWNLOAD_INTERRUPT_REASON_NONE) {
     DCHECK(stream.get());
     download_file.reset(file_factory_->CreateFile(
-        *info->save_info, default_download_directory, info->url(),
-        info->referrer_url, delegate_ && delegate_->GenerateFileHash(),
-        std::move(info->save_info->file), std::move(stream),
-        download->GetBoundNetLog(), download->DestinationObserverAsWeakPtr()));
-
-    if (download_file.get() && delegate_) {
-      download_file->SetClientGuid(
-          delegate_->ApplicationClientIdForFileScanning());
-    }
+        std::move(info->save_info), default_download_directory,
+        std::move(stream), download->GetBoundNetLog(),
+        download->DestinationObserverAsWeakPtr()));
   }
+  // It is important to leave info->save_info intact in the case of an interrupt
+  // so that the DownloadItem can salvage what it can out of a failed resumption
+  // attempt.
 
   download->Start(std::move(download_file), std::move(info->request_handle),
                   *info);
@@ -609,6 +592,7 @@ DownloadItem* DownloadManagerImpl::CreateDownloadItem(
     const std::string& last_modified,
     int64_t received_bytes,
     int64_t total_bytes,
+    const std::string& hash,
     DownloadItem::DownloadState state,
     DownloadDangerType danger_type,
     DownloadInterruptReason interrupt_reason,
@@ -618,25 +602,10 @@ DownloadItem* DownloadManagerImpl::CreateDownloadItem(
     return NULL;
   }
   DownloadItemImpl* item = item_factory_->CreatePersistedItem(
-      this,
-      id,
-      current_path,
-      target_path,
-      url_chain,
-      referrer_url,
-      mime_type,
-      original_mime_type,
-      start_time,
-      end_time,
-      etag,
-      last_modified,
-      received_bytes,
-      total_bytes,
-      state,
-      danger_type,
-      interrupt_reason,
-      opened,
-      net::BoundNetLog::Make(net_log_, net::NetLog::SOURCE_DOWNLOAD));
+      this, id, current_path, target_path, url_chain, referrer_url, mime_type,
+      original_mime_type, start_time, end_time, etag, last_modified,
+      received_bytes, total_bytes, hash, state, danger_type, interrupt_reason,
+      opened, net::BoundNetLog::Make(net_log_, net::NetLog::SOURCE_DOWNLOAD));
   downloads_[id] = item;
   FOR_EACH_OBSERVER(Observer, observers_, OnDownloadCreated(this, item));
   DVLOG(20) << __FUNCTION__ << "() download = " << item->DebugString(true);