Remove dependency on //content from history DownloadDatabase

components/history/core/browser/download_constants.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 "components/history/core/browser/download_constants.h"
+
+#include "base/logging.h"
+
+namespace history {
+
+const DownloadState kStateInvalid = -1;
+const DownloadState kStateInProgress = 0;
+const DownloadState kStateComplete = 1;
+const DownloadState kStateCancelled = 2;
+const DownloadState kStateBug140687 = 3;
+const DownloadState kStateInterrupted = 4;
+
+DownloadState IntToDownloadState(int state) {
+  switch (state) {
+    case kStateInProgress:
+    case kStateComplete:
+    case kStateCancelled:
+    case kStateInterrupted:
+      return static_cast<DownloadState>(state);
+    default:
+      NOTREACHED();
+      return kStateInvalid;
+  }
+}
+
+const DownloadDangerType kDangerTypeInvalid = -1;
+const DownloadDangerType kDangerTypeNotDangerous = 0;
+const DownloadDangerType kDangerTypeDangerousFile = 1;
+const DownloadDangerType kDangerTypeDangerousUrl = 2;
+const DownloadDangerType kDangerTypeDangerousContent = 3;
+const DownloadDangerType kDangerTypeMaybeDangerousContent = 4;
+const DownloadDangerType kDangerTypeUncommonContent = 5;
+const DownloadDangerType kDangerTypeUserValidated = 6;
+const DownloadDangerType kDangerTypeDangerousHost = 7;
+const DownloadDangerType kDangerTypePotentiallyUnwanted = 8;
+
+DownloadDangerType IntToDownloadDangerType(int state) {
+  switch (state) {
+    case kDangerTypeNotDangerous:
+    case kDangerTypeDangerousFile:
+    case kDangerTypeDangerousUrl:
+    case kDangerTypeDangerousContent:
+    case kDangerTypeMaybeDangerousContent:
+    case kDangerTypeUncommonContent:
+    case kDangerTypeUserValidated:
+    case kDangerTypeDangerousHost:
+    case kDangerTypePotentiallyUnwanted:
+      return static_cast<DownloadState>(state);
+    default:
+      NOTREACHED();
+      return kDangerTypeInvalid;
+  }
+}
+
+const DownloadId kInvalidDownloadId = 0;
+
+}  // namespace history