Remove dependency on //content from history DownloadDatabase

chrome/browser/history/history_backend.cc

Index: chrome/browser/history/history_backend.cc
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 53d16737d4d1a6baf4dc48ba3527b6b8788af1bc..97e0d4276f3f4a419dc2bacc1dbb4d1fc17d9052 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -24,7 +24,6 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "chrome/browser/chrome_notification_types.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
@@ -35,6 +34,8 @@
 #include "chrome/common/importer/imported_favicon_usage.h"
 #include "chrome/common/url_constants.h"
 #include "components/favicon_base/select_favicon_frames.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_backend_observer.h"
 #include "components/history/core/browser/history_client.h"
 #include "components/history/core/browser/history_constants.h"
@@ -1112,7 +1113,7 @@ void HistoryBackend::RemoveObserver(HistoryBackendObserver* observer) {
 // Downloads -------------------------------------------------------------------
 
 uint32 HistoryBackend::GetNextDownloadId() {
-  return db_ ? db_->GetNextDownloadId() : content::DownloadItem::kInvalidId;
+  return db_ ? db_->GetNextDownloadId() : kInvalidDownloadId;
 }
 
 // Get all the download entries from the database.