Remove dependency on //content from history DownloadDatabase

Move the mapping between content enumeration from download_row.h and
download_database.h into an embedder specific file and provide a
content implementation.

BUG=371836

Review URL: https://codereview.chromium.org/833033002

Cr-Commit-Position: refs/heads/master@{#311057}

35 files changed, 792 insertions, 407 deletions

diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index d4c4510..daf5bad 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -226,6 +226,7 @@ static_library("browser") {
       "//components/app_modal",
       "//components/autofill/content/browser",
       "//components/dom_distiller/content",
+      "//components/history/content/browser",
       "//components/keyed_service/content",
       "//components/navigation_interception",
       "//components/password_manager/content/browser",
diff --git a/chrome/browser/download/download_browsertest.cc b/chrome/browser/download/download_browsertest.cc
index 6237ab5..d315768 100644
--- a/chrome/browser/download/download_browsertest.cc
+++ b/chrome/browser/download/download_browsertest.cc
@@ -40,7 +40,6 @@
 #include "chrome/browser/extensions/extension_install_prompt.h"
 #include "chrome/browser/extensions/extension_install_prompt_show_params.h"
 #include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/infobars/infobar_service.h"
@@ -65,6 +64,9 @@
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/test_switches.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/infobars/core/confirm_infobar_delegate.h"
 #include "components/infobars/core/infobar.h"
 #include "content/public/browser/download_interrupt_reasons.h"
@@ -1774,12 +1776,12 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadHistoryCheck) {
   ASSERT_EQ(2u, row.url_chain.size());
   EXPECT_EQ(redirect_url.spec(), row.url_chain[0].spec());
   EXPECT_EQ(download_url.spec(), row.url_chain[1].spec());
-  EXPECT_EQ(content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS, row.danger_type);
+  EXPECT_EQ(history::DownloadDangerType::NOT_DANGEROUS, row.danger_type);
   EXPECT_LE(start, row.start_time);
   EXPECT_EQ(URLRequestSlowDownloadJob::kFirstDownloadSize, row.received_bytes);
   EXPECT_EQ(URLRequestSlowDownloadJob::kFirstDownloadSize
             + URLRequestSlowDownloadJob::kSecondDownloadSize, row.total_bytes);
-  EXPECT_EQ(content::DownloadItem::IN_PROGRESS, row.state);
+  EXPECT_EQ(history::DownloadState::IN_PROGRESS, row.state);
   EXPECT_FALSE(row.opened);
 
   // Finish the download.  We're ok relying on the history to be flushed
@@ -1807,15 +1809,16 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadHistoryCheck) {
   ASSERT_EQ(2u, row1.url_chain.size());
   EXPECT_EQ(redirect_url.spec(), row1.url_chain[0].spec());
   EXPECT_EQ(download_url.spec(), row1.url_chain[1].spec());
-  EXPECT_EQ(content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS, row1.danger_type);
+  EXPECT_EQ(history::DownloadDangerType::NOT_DANGEROUS, row1.danger_type);
   EXPECT_LE(start, row1.start_time);
   EXPECT_GE(end, row1.end_time);
   EXPECT_EQ(URLRequestSlowDownloadJob::kFirstDownloadSize,
             row1.received_bytes);
   EXPECT_EQ(URLRequestSlowDownloadJob::kFirstDownloadSize
             + URLRequestSlowDownloadJob::kSecondDownloadSize, row1.total_bytes);
-  EXPECT_EQ(content::DownloadItem::INTERRUPTED, row1.state);
-  EXPECT_EQ(content::DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED,
+  EXPECT_EQ(history::DownloadState::INTERRUPTED, row1.state);
+  EXPECT_EQ(history::ToHistoryDownloadInterruptReason(
+                content::DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED),
             row1.interrupt_reason);
   EXPECT_FALSE(row1.opened);
 }
@@ -1857,9 +1860,9 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadHistoryDangerCheck) {
   EXPECT_NE(DownloadTargetDeterminer::GetCrDownloadPath(
                 DestinationFile(browser(), file)),
             row.current_path);
-  EXPECT_EQ(content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE, row.danger_type);
+  EXPECT_EQ(history::DownloadDangerType::DANGEROUS_FILE, row.danger_type);
   EXPECT_LE(start, row.start_time);
-  EXPECT_EQ(content::DownloadItem::IN_PROGRESS, row.state);
+  EXPECT_EQ(history::DownloadState::IN_PROGRESS, row.state);
   EXPECT_FALSE(row.opened);
 
   // Validate the download and wait for it to finish.
@@ -1877,9 +1880,9 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadHistoryDangerCheck) {
   history::DownloadRow& row1(downloads_in_database->at(0));
   EXPECT_EQ(DestinationFile(browser(), file), row1.target_path);
   EXPECT_EQ(DestinationFile(browser(), file), row1.current_path);
-  EXPECT_EQ(content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED, row1.danger_type);
+  EXPECT_EQ(history::DownloadDangerType::USER_VALIDATED, row1.danger_type);
   EXPECT_LE(start, row1.start_time);
-  EXPECT_EQ(content::DownloadItem::COMPLETE, row1.state);
+  EXPECT_EQ(history::DownloadState::COMPLETE, row1.state);
   EXPECT_FALSE(row1.opened);
   // Not checking file size--not relevant to the point of the test, and
   // the file size is actually different on Windows and other platforms,
diff --git a/chrome/browser/download/download_history.cc b/chrome/browser/download/download_history.cc
index 9e96082..3ee464c 100644
--- a/chrome/browser/download/download_history.cc
+++ b/chrome/browser/download/download_history.cc
@@ -30,9 +30,10 @@
 
 #include "base/metrics/histogram.h"
 #include "chrome/browser/download/download_crx_util.h"
-#include "chrome/browser/history/download_database.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_service.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "components/history/core/browser/download_database.h"
+#include "components/history/core/browser/download_row.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
@@ -135,10 +136,10 @@ history::DownloadRow GetDownloadRow(
       item->GetLastModifiedTime(),
       item->GetReceivedBytes(),
       item->GetTotalBytes(),
-      item->GetState(),
-      item->GetDangerType(),
-      item->GetLastReason(),
-      item->GetId(),
+      history::ToHistoryDownloadState(item->GetState()),
+      history::ToHistoryDownloadDangerType(item->GetDangerType()),
+      history::ToHistoryDownloadInterruptReason(item->GetLastReason()),
+      history::ToHistoryDownloadId(item->GetId()),
       item->GetOpened(),
       by_ext_id,
       by_ext_name);
@@ -257,7 +258,7 @@ void DownloadHistory::QueryCallback(scoped_ptr<InfoVector> infos) {
     return;
   for (InfoVector::const_iterator it = infos->begin();
        it != infos->end(); ++it) {
-    loading_id_ = it->id;
+    loading_id_ = history::ToContentDownloadId(it->id);
     content::DownloadItem* item = notifier_.GetManager()->CreateDownloadItem(
         loading_id_,
         it->current_path,
@@ -272,9 +273,9 @@ void DownloadHistory::QueryCallback(scoped_ptr<InfoVector> infos) {
         it->last_modified,
         it->received_bytes,
         it->total_bytes,
-        it->state,
-        it->danger_type,
-        it->interrupt_reason,
+        history::ToContentDownloadState(it->state),
+        history::ToContentDownloadDangerType(it->danger_type),
+        history::ToContentDownloadInterruptReason(it->interrupt_reason),
         it->opened);
 #if defined(ENABLE_EXTENSIONS)
     if (!it->by_ext_id.empty() && !it->by_ext_name.empty()) {
diff --git a/chrome/browser/download/download_history_unittest.cc b/chrome/browser/download/download_history_unittest.cc
index e11d0a8..5c43c67 100644
--- a/chrome/browser/download/download_history_unittest.cc
+++ b/chrome/browser/download/download_history_unittest.cc
@@ -8,9 +8,10 @@
 #include "base/rand_util.h"
 #include "base/stl_util.h"
 #include "chrome/browser/download/download_history.h"
-#include "chrome/browser/history/download_database.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_service.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "content/public/test/mock_download_item.h"
 #include "content/public/test/mock_download_manager.h"
 #include "content/public/test/test_browser_thread.h"
@@ -228,24 +229,25 @@ class DownloadHistoryTest : public testing::Test {
     EXPECT_CALL(manager(), RemoveObserver(_));
     download_created_index_ = 0;
     for (size_t index = 0; index < infos->size(); ++index) {
+      const history::DownloadRow& row = infos->at(index);
       content::MockDownloadManager::CreateDownloadItemAdapter adapter(
-          infos->at(index).id,
-          infos->at(index).current_path,
-          infos->at(index).target_path,
-          infos->at(index).url_chain,
-          infos->at(index).referrer_url,
-          infos->at(index).mime_type,
-          infos->at(index).original_mime_type,
-          infos->at(index).start_time,
-          infos->at(index).end_time,
-          infos->at(index).etag,
-          infos->at(index).last_modified,
-          infos->at(index).received_bytes,
-          infos->at(index).total_bytes,
-          infos->at(index).state,
-          infos->at(index).danger_type,
-          infos->at(index).interrupt_reason,
-          infos->at(index).opened);
+          history::ToContentDownloadId(row.id),
+          row.current_path,
+          row.target_path,
+          row.url_chain,
+          row.referrer_url,
+          row.mime_type,
+          row.original_mime_type,
+          row.start_time,
+          row.end_time,
+          row.etag,
+          row.last_modified,
+          row.received_bytes,
+          row.total_bytes,
+          history::ToContentDownloadState(row.state),
+          history::ToContentDownloadDangerType(row.danger_type),
+          history::ToContentDownloadInterruptReason(row.interrupt_reason),
+          row.opened);
       EXPECT_CALL(manager(), MockCreateDownloadItem(adapter))
         .WillOnce(DoAll(
             InvokeWithoutArgs(
@@ -405,10 +407,11 @@ class DownloadHistoryTest : public testing::Test {
     info->last_modified = last_modified;
     info->received_bytes = received_bytes;
     info->total_bytes = total_bytes;
-    info->state = state;
-    info->danger_type = danger_type;
-    info->interrupt_reason = interrupt_reason;
-    info->id = id;
+    info->state = history::ToHistoryDownloadState(state);
+    info->danger_type = history::ToHistoryDownloadDangerType(danger_type);
+    info->interrupt_reason =
+        history::ToHistoryDownloadInterruptReason(interrupt_reason);
+    info->id = history::ToHistoryDownloadId(id);
     info->opened = opened;
     info->by_ext_id = by_extension_id;
     info->by_ext_name = by_extension_name;
@@ -661,21 +664,22 @@ TEST_F(DownloadHistoryTest, DownloadHistoryTest_Update) {
   // state
   EXPECT_CALL(item(0), GetState())
       .WillRepeatedly(Return(content::DownloadItem::INTERRUPTED));
-  info.state = content::DownloadItem::INTERRUPTED;
+  info.state = history::DownloadState::INTERRUPTED;
   item(0).NotifyObserversDownloadUpdated();
   ExpectDownloadUpdated(info);
 
   // danger_type
   EXPECT_CALL(item(0), GetDangerType())
       .WillRepeatedly(Return(content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT));
-  info.danger_type = content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT;
+  info.danger_type = history::DownloadDangerType::DANGEROUS_CONTENT;
   item(0).NotifyObserversDownloadUpdated();
   ExpectDownloadUpdated(info);
 
   // interrupt_reason
   EXPECT_CALL(item(0), GetLastReason())
       .WillRepeatedly(Return(content::DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED));
-  info.interrupt_reason = content::DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
+  info.interrupt_reason = history::ToHistoryDownloadInterruptReason(
+      content::DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED);
   item(0).NotifyObserversDownloadUpdated();
   ExpectDownloadUpdated(info);
 
diff --git a/chrome/browser/download/download_ui_controller_unittest.cc b/chrome/browser/download/download_ui_controller_unittest.cc
index 59aa68b..23b21be 100644
--- a/chrome/browser/download/download_ui_controller_unittest.cc
+++ b/chrome/browser/download/download_ui_controller_unittest.cc
@@ -13,9 +13,9 @@
 #include "chrome/browser/download/download_service.h"
 #include "chrome/browser/download/download_service_factory.h"
 #include "chrome/browser/download/download_ui_controller.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
+#include "components/history/core/browser/download_row.h"
 #include "content/public/test/mock_download_item.h"
 #include "content/public/test/mock_download_manager.h"
 #include "testing/gmock/include/gmock/gmock.h"
diff --git a/chrome/browser/download/save_page_browsertest.cc b/chrome/browser/download/save_page_browsertest.cc
index b3e3b58..a6d4795 100644
--- a/chrome/browser/download/save_page_browsertest.cc
+++ b/chrome/browser/download/save_page_browsertest.cc
@@ -19,7 +19,6 @@
 #include "chrome/browser/download/download_service.h"
 #include "chrome/browser/download/download_service_factory.h"
 #include "chrome/browser/download/save_package_file_picker.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/net/url_request_mock_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
@@ -32,6 +31,8 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/notification_service.h"
@@ -141,7 +142,7 @@ bool DownloadStoredProperly(
     const GURL& expected_url,
     const base::FilePath& expected_path,
     int64 num_files,
-    DownloadItem::DownloadState expected_state,
+    history::DownloadState expected_state,
     DownloadItem* item,
     const history::DownloadRow& info) {
   // This function may be called multiple times for a given test. Returning
@@ -383,7 +384,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, MAYBE_SaveHTMLOnly) {
   GetDestinationPaths("a", &full_file_name, &dir);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, 1,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
@@ -414,7 +415,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, DISABLED_SaveHTMLOnlyCancel) {
   DownloadItemCreatedObserver creation_observer(manager);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, -1,
-      DownloadItem::CANCELLED));
+      history::DownloadState::CANCELLED));
   // -1 to disable number of files check; we don't update after cancel, and
   // we don't know when the single file completed in relationship to
   // the cancel.
@@ -510,7 +511,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, MAYBE_SaveViewSourceHTMLOnly) {
   GetDestinationPaths("a", &full_file_name, &dir);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, actual_page_url, full_file_name, 1,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
@@ -544,7 +545,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, MAYBE_SaveCompleteHTML) {
   GetDestinationPaths("b", &full_file_name, &dir);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, 3,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
@@ -639,7 +640,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, MAYBE_FileNameFromPageTitle) {
       "Test page for saving page feature_files");
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, 3,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
@@ -680,7 +681,7 @@ IN_PROC_BROWSER_TEST_F(SavePageBrowserTest, MAYBE_RemoveFromList) {
   GetDestinationPaths("a", &full_file_name, &dir);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, 1,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
@@ -770,7 +771,7 @@ IN_PROC_BROWSER_TEST_F(SavePageAsMHTMLBrowserTest, SavePageAsMHTML) {
   SavePackageFilePicker::SetShouldPromptUser(false);
   DownloadPersistedObserver persisted(browser()->profile(), base::Bind(
       &DownloadStoredProperly, url, full_file_name, -1,
-      DownloadItem::COMPLETE));
+      history::DownloadState::COMPLETE));
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   SavePackageFinishedObserver observer(
diff --git a/chrome/browser/extensions/api/downloads/downloads_api_browsertest.cc b/chrome/browser/extensions/api/downloads/downloads_api_browsertest.cc
index 0060fc0..6028304 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api_browsertest.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api_browsertest.cc
@@ -23,7 +23,6 @@
 #include "chrome/browser/extensions/browser_action_test_util.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_function_test_utils.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/net/url_request_mock_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
diff --git a/chrome/browser/history/download_row.cc b/chrome/browser/history/download_row.cc
deleted file mode 100644
index 6621dac6..0000000
--- a/chrome/browser/history/download_row.cc
+++ /dev/null
@@ -1,63 +0,0 @@
-// 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 "chrome/browser/history/download_row.h"
-
-namespace history {
-
-DownloadRow::DownloadRow()
-    : received_bytes(0),
-      total_bytes(0),
-      state(content::DownloadItem::IN_PROGRESS),
-      danger_type(content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS),
-      interrupt_reason(content::DOWNLOAD_INTERRUPT_REASON_NONE),
-      id(content::DownloadItem::kInvalidId),
-      opened(false) {
-}
-
-DownloadRow::DownloadRow(
-    const base::FilePath& current_path,
-    const base::FilePath& target_path,
-    const std::vector<GURL>& url_chain,
-    const GURL& referrer,
-    const std::string& mime_type,
-    const std::string& original_mime_type,
-    const base::Time& start,
-    const base::Time& end,
-    const std::string& etag,
-    const std::string& last_modified,
-    int64 received,
-    int64 total,
-    content::DownloadItem::DownloadState download_state,
-    content::DownloadDangerType danger_type,
-    content::DownloadInterruptReason interrupt_reason,
-    uint32 id,
-    bool download_opened,
-    const std::string& ext_id,
-    const std::string& ext_name)
-    : current_path(current_path),
-      target_path(target_path),
-      url_chain(url_chain),
-      referrer_url(referrer),
-      mime_type(mime_type),
-      original_mime_type(original_mime_type),
-      start_time(start),
-      end_time(end),
-      etag(etag),
-      last_modified(last_modified),
-      received_bytes(received),
-      total_bytes(total),
-      state(download_state),
-      danger_type(danger_type),
-      interrupt_reason(interrupt_reason),
-      id(id),
-      opened(download_opened),
-      by_ext_id(ext_id),
-      by_ext_name(ext_name) {
-}
-
-DownloadRow::~DownloadRow() {
-}
-
-}  // namespace history
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 2054fba..8ac71f2 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"
@@ -1111,7 +1112,7 @@ 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.
diff --git a/chrome/browser/history/history_database.cc b/chrome/browser/history/history_database.cc
index a0786eb..0eb7a90 100644
--- a/chrome/browser/history/history_database.cc
+++ b/chrome/browser/history/history_database.cc
@@ -14,6 +14,8 @@
 #include "base/rand_util.h"
 #include "base/strings/string_util.h"
 #include "base/time/time.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "content/public/browser/download_interrupt_reasons.h"
 #include "sql/transaction.h"
 
 #if defined(OS_MACOSX)
@@ -33,7 +35,11 @@ const char kEarlyExpirationThresholdKey[] = "early_expiration_threshold";
 
 }  // namespace
 
-HistoryDatabase::HistoryDatabase() {
+HistoryDatabase::HistoryDatabase()
+    : DownloadDatabase(ToHistoryDownloadInterruptReason(
+                           content::DOWNLOAD_INTERRUPT_REASON_NONE),
+                       ToHistoryDownloadInterruptReason(
+                           content::DOWNLOAD_INTERRUPT_REASON_CRASH)) {
 }
 
 HistoryDatabase::~HistoryDatabase() {
diff --git a/chrome/browser/history/history_database.h b/chrome/browser/history/history_database.h
index 4a4ac9e..687ef88 100644
--- a/chrome/browser/history/history_database.h
+++ b/chrome/browser/history/history_database.h
@@ -9,7 +9,7 @@
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "build/build_config.h"
-#include "chrome/browser/history/download_database.h"
+#include "components/history/core/browser/download_database.h"
 #include "components/history/core/browser/url_database.h"
 #include "components/history/core/browser/visit_database.h"
 #include "components/history/core/browser/visitsegment_database.h"
diff --git a/chrome/browser/history/history_service.cc b/chrome/browser/history/history_service.cc
index f010de6..8eb490b 100644
--- a/chrome/browser/history/history_service.cc
+++ b/chrome/browser/history/history_service.cc
@@ -31,7 +31,6 @@
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
@@ -46,6 +45,7 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "components/dom_distiller/core/url_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_client.h"
 #include "components/history/core/browser/history_service_observer.h"
 #include "components/history/core/browser/history_types.h"
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index d344ca5..b6022f5 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -42,7 +42,6 @@
 #include "base/task/cancelable_task_tracker.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/history/history_database.h"
 #include "chrome/browser/history/history_notifications.h"
@@ -52,6 +51,9 @@
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_constants.h"
 #include "components/history/core/browser/history_db_task.h"
 #include "components/history/core/browser/in_memory_database.h"
@@ -180,9 +182,7 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
     base::MessageLoop::current()->Run();
   }
 
-  bool AddDownload(uint32 id,
-                   DownloadItem::DownloadState state,
-                   const Time& time) {
+  bool AddDownload(uint32 id, DownloadState state, const Time& time) {
     std::vector<GURL> url_chain;
     url_chain.push_back(GURL("foo-url"));
 
@@ -199,8 +199,9 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
                          0,
                          512,
                          state,
-                         content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
-                         content::DOWNLOAD_INTERRUPT_REASON_NONE,
+                         DownloadDangerType::NOT_DANGEROUS,
+                         ToHistoryDownloadInterruptReason(
+                            content::DOWNLOAD_INTERRUPT_REASON_NONE),
                          id,
                          false,
                          "by_ext_id",
@@ -250,7 +251,7 @@ TEST_F(HistoryBackendDBTest, ClearBrowsingData_Downloads) {
   // was removed.
   Time now = Time();
   uint32 id = 1;
-  EXPECT_TRUE(AddDownload(id, DownloadItem::COMPLETE, Time()));
+  EXPECT_TRUE(AddDownload(id, DownloadState::COMPLETE, Time()));
   db_->QueryDownloads(&downloads);
   EXPECT_EQ(1U, downloads.size());
 
@@ -266,9 +267,8 @@ TEST_F(HistoryBackendDBTest, ClearBrowsingData_Downloads) {
   EXPECT_EQ(now, downloads[0].end_time);
   EXPECT_EQ(0, downloads[0].received_bytes);
   EXPECT_EQ(512, downloads[0].total_bytes);
-  EXPECT_EQ(DownloadItem::COMPLETE, downloads[0].state);
-  EXPECT_EQ(content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
-            downloads[0].danger_type);
+  EXPECT_EQ(DownloadState::COMPLETE, downloads[0].state);
+  EXPECT_EQ(DownloadDangerType::NOT_DANGEROUS, downloads[0].danger_type);
   EXPECT_EQ(content::DOWNLOAD_INTERRUPT_REASON_NONE,
             downloads[0].interrupt_reason);
   EXPECT_FALSE(downloads[0].opened);
@@ -729,9 +729,9 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadRowCreateAndDelete) {
 
   // Add some downloads.
   uint32 id1 = 1, id2 = 2, id3 = 3;
-  AddDownload(id1, DownloadItem::COMPLETE, now);
-  AddDownload(id2, DownloadItem::COMPLETE, now + base::TimeDelta::FromDays(2));
-  AddDownload(id3, DownloadItem::COMPLETE, now - base::TimeDelta::FromDays(2));
+  AddDownload(id1, DownloadState::COMPLETE, now);
+  AddDownload(id2, DownloadState::COMPLETE, now + base::TimeDelta::FromDays(2));
+  AddDownload(id3, DownloadState::COMPLETE, now - base::TimeDelta::FromDays(2));
 
   // Confirm that resulted in the correct number of rows in the DB.
   DeleteBackend();
@@ -785,9 +785,10 @@ TEST_F(HistoryBackendDBTest, DownloadNukeRecordsMissingURLs) {
                        std::string(),
                        0,
                        512,
-                       DownloadItem::COMPLETE,
-                       content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
-                       content::DOWNLOAD_INTERRUPT_REASON_NONE,
+                       DownloadState::COMPLETE,
+                       DownloadDangerType::NOT_DANGEROUS,
+                       ToHistoryDownloadInterruptReason(
+                          content::DOWNLOAD_INTERRUPT_REASON_NONE),
                        1,
                        0,
                        "by_ext_id",
@@ -834,7 +835,7 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadInProgressCleanup) {
   base::Time now(base::Time::Now());
 
   // Put an IN_PROGRESS download in the DB.
-  AddDownload(1, DownloadItem::IN_PROGRESS, now);
+  AddDownload(1, DownloadState::IN_PROGRESS, now);
 
   // Confirm that they made it into the DB unchanged.
   DeleteBackend();
@@ -849,7 +850,8 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadInProgressCleanup) {
     sql::Statement statement1(db.GetUniqueStatement(
         "Select state, interrupt_reason from downloads"));
     EXPECT_TRUE(statement1.Step());
-    EXPECT_EQ(DownloadDatabase::kStateInProgress, statement1.ColumnInt(0));
+    EXPECT_EQ(DownloadStateToInt(DownloadState::IN_PROGRESS),
+              statement1.ColumnInt(0));
     EXPECT_EQ(content::DOWNLOAD_INTERRUPT_REASON_NONE, statement1.ColumnInt(1));
     EXPECT_FALSE(statement1.Step());
   }
@@ -860,7 +862,7 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadInProgressCleanup) {
   std::vector<DownloadRow> results;
   db_->QueryDownloads(&results);
   ASSERT_EQ(1u, results.size());
-  EXPECT_EQ(content::DownloadItem::INTERRUPTED, results[0].state);
+  EXPECT_EQ(DownloadState::INTERRUPTED, results[0].state);
   EXPECT_EQ(content::DOWNLOAD_INTERRUPT_REASON_CRASH,
             results[0].interrupt_reason);
 
@@ -879,7 +881,8 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadInProgressCleanup) {
     sql::Statement statement1(db.GetUniqueStatement(
         "Select state, interrupt_reason from downloads"));
     EXPECT_TRUE(statement1.Step());
-    EXPECT_EQ(DownloadDatabase::kStateInterrupted, statement1.ColumnInt(0));
+    EXPECT_EQ(DownloadStateToInt(DownloadState::INTERRUPTED),
+              statement1.ColumnInt(0));
     EXPECT_EQ(content::DOWNLOAD_INTERRUPT_REASON_CRASH,
               statement1.ColumnInt(1));
     EXPECT_FALSE(statement1.Step());
diff --git a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
index 7c311c9..7d18098 100644
--- a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
@@ -19,7 +19,7 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/safe_browsing/csd.pb.h"
 #include "chrome/common/safe_browsing/download_protection_util.h"
-#include "content/public/browser/download_item.h"
+#include "components/history/core/browser/download_constants.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
@@ -85,7 +85,7 @@ const history::DownloadRow* FindMostInteresting(
   for (size_t i = 0; i < downloads.size(); ++i) {
     const history::DownloadRow& row = downloads[i];
     // Ignore incomplete downloads.
-    if (row.state != content::DownloadItem::COMPLETE)
+    if (row.state != history::DownloadState::COMPLETE)
       continue;
     if (!most_recent_row || IsMoreInterestingThan(row, *most_recent_row))
       most_recent_row = &row;
diff --git a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.h b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.h
index 0f7503d..a3ef0d6 100644
--- a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.h
+++ b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.h
@@ -14,8 +14,8 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/safe_browsing/incident_reporting/download_metadata_manager.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_service_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ -28,10 +28,6 @@ class NotificationDetails;
 class NotificationSource;
 }
 
-namespace history {
-struct DownloadRow;
-}
-
 namespace safe_browsing {
 
 class ClientIncidentReport_DownloadDetails;
diff --git a/chrome/browser/safe_browsing/incident_reporting/last_download_finder_unittest.cc b/chrome/browser/safe_browsing/incident_reporting/last_download_finder_unittest.cc
index 4897b51..dd11d40 100644
--- a/chrome/browser/safe_browsing/incident_reporting/last_download_finder_unittest.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/last_download_finder_unittest.cc
@@ -15,7 +15,6 @@
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/chrome_history_client_factory.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/web_history_service_factory.h"
@@ -28,6 +27,9 @@
 #include "chrome/test/base/testing_pref_service_syncable.h"
 #include "chrome/test/base/testing_profile.h"
 #include "chrome/test/base/testing_profile_manager.h"
+#include "components/history/content/browser/download_constants_utils.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_constants.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "content/public/test/test_utils.h"
@@ -219,20 +221,21 @@ class LastDownloadFinderTest : public testing::Test {
         std::vector<GURL>(1, GURL("http://www.google.com")),  // url_chain
         GURL(),                                               // referrer
         "application/octet-stream",                           // mime_type
-        "application/octet-stream",                   // original_mime_type
-        now - base::TimeDelta::FromMinutes(10),       // start
-        now - base::TimeDelta::FromMinutes(9),        // end
-        std::string(),                                // etag
-        std::string(),                                // last_modified
-        47LL,                                         // received
-        47LL,                                         // total
-        content::DownloadItem::COMPLETE,              // download_state
-        content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,  // danger_type
-        content::DOWNLOAD_INTERRUPT_REASON_NONE,      // interrupt_reason,
-        1,                                            // id
-        false,                                        // download_opened
-        std::string(),                                // ext_id
-        std::string());                               // ext_name
+        "application/octet-stream",                  // original_mime_type
+        now - base::TimeDelta::FromMinutes(10),      // start
+        now - base::TimeDelta::FromMinutes(9),       // end
+        std::string(),                               // etag
+        std::string(),                               // last_modified
+        47LL,                                        // received
+        47LL,                                        // total
+        history::DownloadState::COMPLETE,            // download_state
+        history::DownloadDangerType::NOT_DANGEROUS,  // danger_type
+        history::ToHistoryDownloadInterruptReason(
+            content::DOWNLOAD_INTERRUPT_REASON_NONE),  // interrupt_reason,
+        1,                                             // id
+        false,                                         // download_opened
+        std::string(),                                 // ext_id
+        std::string());                                // ext_name
   }
 
   void ExpectNoDownloadFound(
diff --git a/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc b/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
index fbc6a48..4d8c060 100644
--- a/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
+++ b/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
@@ -7,7 +7,6 @@
 #include "base/json/json_reader.h"
 #include "base/prefs/pref_service.h"
 #include "base/values.h"
-#include "chrome/browser/history/download_row.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/webui/downloads_dom_handler.h"
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 263c385..25abd54 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1502,10 +1502,6 @@
       'browser/history/chrome_history_client_factory.h',
       'browser/history/delete_directive_handler.cc',
       'browser/history/delete_directive_handler.h',
-      'browser/history/download_database.cc',
-      'browser/history/download_database.h',
-      'browser/history/download_row.cc',
-      'browser/history/download_row.h',
       'browser/history/expire_history_backend.cc',
       'browser/history/expire_history_backend.h',
       'browser/history/history_backend.cc',
@@ -2989,6 +2985,7 @@
             '../cc/cc.gyp:cc',
             '../components/components.gyp:autofill_content_browser',
             '../components/components.gyp:dom_distiller_content',
+            '../components/components.gyp:history_content_browser',
             '../components/components.gyp:keyed_service_content',
             '../components/components.gyp:navigation_interception',
             '../components/components.gyp:packed_ct_ev_whitelist',
diff --git a/components/BUILD.gn b/components/BUILD.gn
index ca44c58..739d387 100644
--- a/components/BUILD.gn
+++ b/components/BUILD.gn
@@ -41,6 +41,7 @@ group("all_components") {
     "//components/feedback",
     "//components/gcm_driver",
     "//components/google/core/browser",
+    "//components/history/content/browser",
     "//components/history/core/browser",
     "//components/history/core/common",
     "//components/history/core/test",
@@ -124,8 +125,9 @@ group("all_components") {
   }
   if (is_ios) {
     deps -= [
-      "//components/keyed_service/content",
       "//components/copresence_endpoints",
+      "//components/history/content/browser",
+      "//components/keyed_service/content",
     ]
   }
 
diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index c9437e5..6c6b332 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -559,6 +559,9 @@
                 # Dependencies of error_page
                 'components.gyp:error_page_renderer',
 
+                # Dependencies of history
+                'components.gyp:history_content_browser',
+
                 # Dependencies of
                 # intercept_navigation_resource_throttle_unittest.cc
                 '../skia/skia.gyp:skia',
diff --git a/components/history.gypi b/components/history.gypi
index 434771a..3335644 100644
--- a/components/history.gypi
+++ b/components/history.gypi
@@ -26,6 +26,13 @@
       ],
       'sources': [
         # Note: sources list duplicated in GN build.
+        'history/core/browser/download_constants.h',
+        'history/core/browser/download_database.cc',
+        'history/core/browser/download_database.h',
+        'history/core/browser/download_row.cc',
+        'history/core/browser/download_row.h',
+        'history/core/browser/download_types.cc',
+        'history/core/browser/download_types.h',
         'history/core/browser/history_backend_notifier.h',
         'history/core/browser/history_backend_observer.h',
         'history/core/browser/history_client.cc',
@@ -119,6 +126,27 @@
     },
   ],
   'conditions': [
+    ['OS!="ios"', {
+      'targets': [
+        {
+          # GN version: //components/history/content/browser
+          'target_name': 'history_content_browser',
+          'type': 'static_library',
+          'include_dirs': [
+            '..',
+          ],
+          'dependencies': [
+            '../base/base.gyp:base',
+            '../content/content.gyp:content_browser',
+            'history_core_browser',
+          ],
+          'sources': [
+            'history/content/browser/download_constants_utils.cc',
+            'history/content/browser/download_constants_utils.h',
+          ],
+        }
+      ],
+    }],
     ['OS=="android"', {
       'targets': [
         {
diff --git a/components/history/README b/components/history/README
new file mode 100644
index 0000000..206d654
--- /dev/null
+++ b/components/history/README
@@ -0,0 +1,13 @@
+History is in the process of becoming a layered compoent
+(https://sites.google.com/a/chromium.org/dev/developers/design-documents/layered-components-design)
+to enable it to be shared cleanly on iOS.
+
+When this process is complete, this component will have the following structure:
+
+core/: shared code that does not depends on src/content/ or src/ios/
+  browser/: browser process code
+  common/: code shared by the browser and the renderer
+content/: driver for the shared code based on the content layer
+  browser/: browser process code
+  common/: code shared by the browser and the renderer
+ios/: driver for the shared code based on src/ios
diff --git a/components/history/content/DEPS b/components/history/content/DEPS
new file mode 100644
index 0000000..60dbcf4
--- /dev/null
+++ b/components/history/content/DEPS
@@ -0,0 +1,3 @@
+include_rules = [
+  "+content",
+]
diff --git a/components/history/content/browser/BUILD.gn b/components/history/content/browser/BUILD.gn
new file mode 100644
index 0000000..30628c2
--- /dev/null
+++ b/components/history/content/browser/BUILD.gn
@@ -0,0 +1,16 @@
+# 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.
+
+static_library("browser") {
+  sources = [
+    "download_constants_utils.cc",
+    "download_constants_utils.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/history/core/browser",
+    "//content/public/browser",
+  ]
+}
diff --git a/components/history/content/browser/download_constants_utils.cc b/components/history/content/browser/download_constants_utils.cc
new file mode 100644
index 0000000..ffdfe23
--- /dev/null
+++ b/components/history/content/browser/download_constants_utils.cc
@@ -0,0 +1,129 @@
+// 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/content/browser/download_constants_utils.h"
+
+#include "base/logging.h"
+#include "components/history/core/browser/download_constants.h"
+
+namespace history {
+
+content::DownloadItem::DownloadState ToContentDownloadState(
+    DownloadState state) {
+  switch (state) {
+    case DownloadState::IN_PROGRESS:
+      return content::DownloadItem::IN_PROGRESS;
+    case DownloadState::COMPLETE:
+      return content::DownloadItem::COMPLETE;
+    case DownloadState::CANCELLED:
+      return content::DownloadItem::CANCELLED;
+    case DownloadState::INTERRUPTED:
+      return content::DownloadItem::INTERRUPTED;
+    case DownloadState::INVALID:
+    case DownloadState::BUG_140687:
+      NOTREACHED();
+      return content::DownloadItem::MAX_DOWNLOAD_STATE;
+  }
+  NOTREACHED();
+  return content::DownloadItem::MAX_DOWNLOAD_STATE;
+}
+
+DownloadState ToHistoryDownloadState(
+    content::DownloadItem::DownloadState state) {
+  switch (state) {
+    case content::DownloadItem::IN_PROGRESS:
+      return DownloadState::IN_PROGRESS;
+    case content::DownloadItem::COMPLETE:
+      return DownloadState::COMPLETE;
+    case content::DownloadItem::CANCELLED:
+      return DownloadState::CANCELLED;
+    case content::DownloadItem::INTERRUPTED:
+      return DownloadState::INTERRUPTED;
+    case content::DownloadItem::MAX_DOWNLOAD_STATE:
+      NOTREACHED();
+      return DownloadState::INVALID;
+  }
+  NOTREACHED();
+  return DownloadState::INVALID;
+}
+
+content::DownloadDangerType ToContentDownloadDangerType(
+    DownloadDangerType danger_type) {
+  switch (danger_type) {
+    case DownloadDangerType::NOT_DANGEROUS:
+      return content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS;
+    case DownloadDangerType::DANGEROUS_FILE:
+      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE;
+    case DownloadDangerType::DANGEROUS_URL:
+      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL;
+    case DownloadDangerType::DANGEROUS_CONTENT:
+      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT;
+    case DownloadDangerType::MAYBE_DANGEROUS_CONTENT:
+      return content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT;
+    case DownloadDangerType::UNCOMMON_CONTENT:
+      return content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT;
+    case DownloadDangerType::USER_VALIDATED:
+      return content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED;
+    case DownloadDangerType::DANGEROUS_HOST:
+      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_HOST;
+    case DownloadDangerType::POTENTIALLY_UNWANTED:
+      return content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED;
+    case DownloadDangerType::INVALID:
+      NOTREACHED();
+      return content::DOWNLOAD_DANGER_TYPE_MAX;
+  }
+  NOTREACHED();
+  return content::DOWNLOAD_DANGER_TYPE_MAX;
+}
+
+DownloadDangerType ToHistoryDownloadDangerType(
+    content::DownloadDangerType danger_type) {
+  switch (danger_type) {
+    case content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS:
+      return DownloadDangerType::NOT_DANGEROUS;
+    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE:
+      return DownloadDangerType::DANGEROUS_FILE;
+    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL:
+      return DownloadDangerType::DANGEROUS_URL;
+    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT:
+      return DownloadDangerType::DANGEROUS_CONTENT;
+    case content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT:
+      return DownloadDangerType::MAYBE_DANGEROUS_CONTENT;
+    case content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT:
+      return DownloadDangerType::UNCOMMON_CONTENT;
+    case content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED:
+      return DownloadDangerType::USER_VALIDATED;
+    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_HOST:
+      return DownloadDangerType::DANGEROUS_HOST;
+    case content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED:
+      return DownloadDangerType::POTENTIALLY_UNWANTED;
+    default:
+      NOTREACHED();
+      return DownloadDangerType::INVALID;
+  }
+  NOTREACHED();
+  return DownloadDangerType::INVALID;
+}
+
+content::DownloadInterruptReason ToContentDownloadInterruptReason(
+    DownloadInterruptReason interrupt_reason) {
+  return static_cast<content::DownloadInterruptReason>(interrupt_reason);
+}
+
+DownloadInterruptReason ToHistoryDownloadInterruptReason(
+    content::DownloadInterruptReason interrupt_reason) {
+  return static_cast<DownloadInterruptReason>(interrupt_reason);
+}
+
+uint32 ToContentDownloadId(DownloadId id) {
+  DCHECK_NE(id, kInvalidDownloadId);
+  return static_cast<uint32>(id);
+}
+
+DownloadId ToHistoryDownloadId(uint32 id) {
+  DCHECK_NE(id, content::DownloadItem::kInvalidId);
+  return static_cast<DownloadId>(id);
+}
+
+}  // namespace history
diff --git a/components/history/content/browser/download_constants_utils.h b/components/history/content/browser/download_constants_utils.h
new file mode 100644
index 0000000..2529dc7
--- /dev/null
+++ b/components/history/content/browser/download_constants_utils.h
@@ -0,0 +1,47 @@
+// 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.
+
+#ifndef COMPONENTS_HISTORY_CONTENT_BROWSER_DOWNLOAD_CONSTANTS_UTILS_H_
+#define COMPONENTS_HISTORY_CONTENT_BROWSER_DOWNLOAD_CONSTANTS_UTILS_H_
+
+#include <string>
+
+#include "components/history/core/browser/download_types.h"
+#include "content/public/browser/download_danger_type.h"
+#include "content/public/browser/download_interrupt_reasons.h"
+#include "content/public/browser/download_item.h"
+
+namespace history {
+
+// Utility functions to convert between content::DownloadItem::DownloadState
+// enumeration and history::DownloadState constants.
+content::DownloadItem::DownloadState ToContentDownloadState(
+    DownloadState state);
+DownloadState ToHistoryDownloadState(
+    content::DownloadItem::DownloadState state);
+
+// Utility functions to convert between content::DownloadDangerType enumeration
+// and history::DownloadDangerType constants.
+content::DownloadDangerType ToContentDownloadDangerType(
+    DownloadDangerType danger_type);
+DownloadDangerType ToHistoryDownloadDangerType(
+    content::DownloadDangerType danger_type);
+
+// Utility functions to convert between content::DownloadInterrupReason
+// enumeration and history::DownloadInterruptReason type (value have no
+// meaning in history, but have a different type to avoid bugs due to
+// implicit conversions).
+content::DownloadInterruptReason ToContentDownloadInterruptReason(
+    DownloadInterruptReason interrupt_reason);
+DownloadInterruptReason ToHistoryDownloadInterruptReason(
+    content::DownloadInterruptReason interrupt_reason);
+
+// Utility functions to convert between content download id values and
+// history::DownloadId type (value have no meaning in history, except
+// for kInvalidDownloadId).
+uint32 ToContentDownloadId(DownloadId id);
+DownloadId ToHistoryDownloadId(uint32 id);
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CONTENT_BROWSER_DOWNLOAD_CONSTANTS_UTILS_H_
diff --git a/components/history/core/DEPS b/components/history/core/DEPS
new file mode 100644
index 0000000..970da79
--- /dev/null
+++ b/components/history/core/DEPS
@@ -0,0 +1,3 @@
+include_rules = [
+  "-components/history/content",
+]
diff --git a/components/history/core/browser/BUILD.gn b/components/history/core/browser/BUILD.gn
index 977ea49..6494dc5 100644
--- a/components/history/core/browser/BUILD.gn
+++ b/components/history/core/browser/BUILD.gn
@@ -6,6 +6,13 @@ import("//third_party/protobuf/proto_library.gni")
 
 static_library("browser") {
   sources = [
+    "download_constants.h",
+    "download_database.cc",
+    "download_database.h",
+    "download_row.cc",
+    "download_row.h",
+    "download_types.cc",
+    "download_types.h",
     "history_backend_notifier.h",
     "history_backend_observer.h",
     "history_client.cc",
diff --git a/components/history/core/browser/download_constants.h b/components/history/core/browser/download_constants.h
new file mode 100644
index 0000000..ea21725
--- /dev/null
+++ b/components/history/core/browser/download_constants.h
@@ -0,0 +1,47 @@
+// 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.
+
+#ifndef COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_CONSTANTS_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_CONSTANTS_H_
+
+#include "components/history/core/browser/download_types.h"
+
+namespace history {
+
+// DownloadState represents the state of a DownloadRow saved into the
+// DownloadDatabase. The values must not be changed as they are saved
+// to disk in the database.
+enum class DownloadState {
+  INVALID = -1,
+  IN_PROGRESS = 0,
+  COMPLETE = 1,
+  CANCELLED = 2,
+  BUG_140687 = 3,
+  INTERRUPTED = 4,
+};
+
+// DownloadDangerType represents the danger of a DownloadRow into the
+// DownloadDatabase. The values must not be changed as they are saved
+// to disk in the database.
+enum class DownloadDangerType {
+  INVALID = -1,
+  NOT_DANGEROUS = 0,
+  DANGEROUS_FILE = 1,
+  DANGEROUS_URL = 2,
+  DANGEROUS_CONTENT = 3,
+  MAYBE_DANGEROUS_CONTENT = 4,
+  UNCOMMON_CONTENT = 5,
+  USER_VALIDATED = 6,
+  DANGEROUS_HOST = 7,
+  POTENTIALLY_UNWANTED = 8,
+};
+
+// DownloadId represents the id of a DownloadRow into the DownloadDatabase.
+// The value is controlled by the embedder except for the reserved id
+// kInvalidDownloadId.
+extern const DownloadId kInvalidDownloadId;
+
+}  // namespace
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_CONSTANTS_H_
diff --git a/chrome/browser/history/download_database.cc b/components/history/core/browser/download_database.cc
index 9461e45..e699bea6 100644
--- a/chrome/browser/history/download_database.cc
+++ b/components/history/core/browser/download_database.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/history/download_database.h"
+#include "components/history/core/browser/download_database.h"
 
 #include <limits>
 #include <string>
@@ -17,14 +17,11 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
-#include "chrome/browser/history/download_row.h"
+#include "components/history/core/browser/download_constants.h"
+#include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_types.h"
-#include "content/public/browser/download_interrupt_reasons.h"
-#include "content/public/browser/download_item.h"
 #include "sql/statement.h"
 
-using content::DownloadItem;
-
 namespace history {
 
 namespace {
@@ -41,7 +38,8 @@ enum DroppedReason {
 #if defined(OS_POSIX)
 
 // Binds/reads the given file path to the given column of the given statement.
-void BindFilePath(sql::Statement& statement, const base::FilePath& path,
+void BindFilePath(sql::Statement& statement,
+                  const base::FilePath& path,
                   int col) {
   statement.BindString(col, path.value());
 }
@@ -52,7 +50,8 @@ base::FilePath ColumnFilePath(sql::Statement& statement, int col) {
 #else
 
 // See above.
-void BindFilePath(sql::Statement& statement, const base::FilePath& path,
+void BindFilePath(sql::Statement& statement,
+                  const base::FilePath& path,
                   int col) {
   statement.BindString16(col, path.value());
 }
@@ -64,121 +63,21 @@ base::FilePath ColumnFilePath(sql::Statement& statement, int col) {
 
 }  // namespace
 
-// These constants and the transformation functions below are used to allow
-// DownloadItem::DownloadState and DownloadDangerType to change without
-// breaking the database schema.
-// They guarantee that the values of the |state| field in the database are one
-// of the values returned by StateToInt, and that the values of the |state|
-// field of the DownloadRows returned by QueryDownloads() are one of the values
-// returned by IntToState().
-const int DownloadDatabase::kStateInvalid = -1;
-const int DownloadDatabase::kStateInProgress = 0;
-const int DownloadDatabase::kStateComplete = 1;
-const int DownloadDatabase::kStateCancelled = 2;
-const int DownloadDatabase::kStateBug140687 = 3;
-const int DownloadDatabase::kStateInterrupted = 4;
-
-const int DownloadDatabase::kDangerTypeInvalid = -1;
-const int DownloadDatabase::kDangerTypeNotDangerous = 0;
-const int DownloadDatabase::kDangerTypeDangerousFile = 1;
-const int DownloadDatabase::kDangerTypeDangerousUrl = 2;
-const int DownloadDatabase::kDangerTypeDangerousContent = 3;
-const int DownloadDatabase::kDangerTypeMaybeDangerousContent = 4;
-const int DownloadDatabase::kDangerTypeUncommonContent = 5;
-const int DownloadDatabase::kDangerTypeUserValidated = 6;
-const int DownloadDatabase::kDangerTypeDangerousHost = 7;
-const int DownloadDatabase::kDangerTypePotentiallyUnwanted = 8;
-
-int DownloadDatabase::StateToInt(DownloadItem::DownloadState state) {
-  switch (state) {
-    case DownloadItem::IN_PROGRESS: return DownloadDatabase::kStateInProgress;
-    case DownloadItem::COMPLETE: return DownloadDatabase::kStateComplete;
-    case DownloadItem::CANCELLED: return DownloadDatabase::kStateCancelled;
-    case DownloadItem::INTERRUPTED: return DownloadDatabase::kStateInterrupted;
-    case DownloadItem::MAX_DOWNLOAD_STATE:
-      NOTREACHED();
-      return DownloadDatabase::kStateInvalid;
-  }
-  NOTREACHED();
-  return DownloadDatabase::kStateInvalid;
-}
-
-DownloadItem::DownloadState DownloadDatabase::IntToState(int state) {
-  switch (state) {
-    case DownloadDatabase::kStateInProgress: return DownloadItem::IN_PROGRESS;
-    case DownloadDatabase::kStateComplete: return DownloadItem::COMPLETE;
-    case DownloadDatabase::kStateCancelled: return DownloadItem::CANCELLED;
-    // We should not need kStateBug140687 here because MigrateDownloadsState()
-    // is called in HistoryDatabase::Init().
-    case DownloadDatabase::kStateInterrupted: return DownloadItem::INTERRUPTED;
-    default: return DownloadItem::MAX_DOWNLOAD_STATE;
-  }
-}
-
-int DownloadDatabase::DangerTypeToInt(content::DownloadDangerType danger_type) {
-  switch (danger_type) {
-    case content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS:
-      return DownloadDatabase::kDangerTypeNotDangerous;
-    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE:
-      return DownloadDatabase::kDangerTypeDangerousFile;
-    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL:
-      return DownloadDatabase::kDangerTypeDangerousUrl;
-    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT:
-      return DownloadDatabase::kDangerTypeDangerousContent;
-    case content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT:
-      return DownloadDatabase::kDangerTypeMaybeDangerousContent;
-    case content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT:
-      return DownloadDatabase::kDangerTypeUncommonContent;
-    case content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED:
-      return DownloadDatabase::kDangerTypeUserValidated;
-    case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_HOST:
-      return DownloadDatabase::kDangerTypeDangerousHost;
-    case content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED:
-      return DownloadDatabase::kDangerTypePotentiallyUnwanted;
-    case content::DOWNLOAD_DANGER_TYPE_MAX:
-      NOTREACHED();
-      return DownloadDatabase::kDangerTypeInvalid;
-  }
-  NOTREACHED();
-  return DownloadDatabase::kDangerTypeInvalid;
-}
-
-content::DownloadDangerType DownloadDatabase::IntToDangerType(int danger_type) {
-  switch (danger_type) {
-    case DownloadDatabase::kDangerTypeNotDangerous:
-      return content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS;
-    case DownloadDatabase::kDangerTypeDangerousFile:
-      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE;
-    case DownloadDatabase::kDangerTypeDangerousUrl:
-      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL;
-    case DownloadDatabase::kDangerTypeDangerousContent:
-      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT;
-    case DownloadDatabase::kDangerTypeMaybeDangerousContent:
-      return content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT;
-    case DownloadDatabase::kDangerTypeUncommonContent:
-      return content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT;
-    case DownloadDatabase::kDangerTypeUserValidated:
-      return content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED;
-    case DownloadDatabase::kDangerTypeDangerousHost:
-      return content::DOWNLOAD_DANGER_TYPE_DANGEROUS_HOST;
-    case DownloadDatabase::kDangerTypePotentiallyUnwanted:
-      return content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED;
-    default:
-      return content::DOWNLOAD_DANGER_TYPE_MAX;
-  }
-}
-
-DownloadDatabase::DownloadDatabase()
+DownloadDatabase::DownloadDatabase(
+    DownloadInterruptReason download_interrupt_no_reason,
+    DownloadInterruptReason download_interrupt_crash)
     : owning_thread_set_(false),
       owning_thread_(0),
-      in_progress_entry_cleanup_completed_(false) {
+      in_progress_entry_cleanup_completed_(false),
+      download_interrupt_no_reason_(download_interrupt_no_reason),
+      download_interrupt_crash_(download_interrupt_crash) {
 }
 
 DownloadDatabase::~DownloadDatabase() {
 }
 
-bool DownloadDatabase::EnsureColumnExists(
-    const std::string& name, const std::string& type) {
+bool DownloadDatabase::EnsureColumnExists(const std::string& name,
+                                          const std::string& type) {
   std::string add_col = "ALTER TABLE downloads ADD COLUMN " + name + " " + type;
   return GetDB().DoesColumnExist("downloads", name.c_str()) ||
          GetDB().Execute(add_col.c_str());
@@ -194,8 +93,8 @@ bool DownloadDatabase::MigrateMimeType() {
 bool DownloadDatabase::MigrateDownloadsState() {
   sql::Statement statement(GetDB().GetUniqueStatement(
       "UPDATE downloads SET state=? WHERE state=?"));
-  statement.BindInt(0, kStateInterrupted);
-  statement.BindInt(1, kStateBug140687);
+  statement.BindInt(0, DownloadStateToInt(DownloadState::INTERRUPTED));
+  statement.BindInt(1, DownloadStateToInt(DownloadState::BUG_140687));
   return statement.Run();
 }
 
@@ -250,8 +149,10 @@ bool DownloadDatabase::MigrateDownloadsReasonPathsAndDangerType() {
       "            (end_time + 11644473600) * 1000000 END, "
       "       opened "
       "FROM downloads_tmp"));
-  statement_populate.BindInt(0, content::DOWNLOAD_INTERRUPT_REASON_NONE);
-  statement_populate.BindInt(1, kDangerTypeNotDangerous);
+  statement_populate.BindInt(
+      0, DownloadInterruptReasonToInt(download_interrupt_no_reason_));
+  statement_populate.BindInt(
+      1, DownloadDangerTypeToInt(DownloadDangerType::NOT_DANGEROUS));
   if (!statement_populate.Run())
     return false;
 
@@ -296,7 +197,7 @@ bool DownloadDatabase::InitDownloadTable() {
       "total_bytes INTEGER NOT NULL,"       // Total size of the download.
       "state INTEGER NOT NULL,"             // 1=complete, 4=interrupted
       "danger_type INTEGER NOT NULL,"       // Danger type, validated.
-      "interrupt_reason INTEGER NOT NULL,"  // content::DownloadInterruptReason
+      "interrupt_reason INTEGER NOT NULL,"  // DownloadInterruptReason
       "end_time INTEGER NOT NULL,"          // When the download completed.
       "opened INTEGER NOT NULL,"            // 1 if it has ever been opened
                                             // else 0
@@ -334,15 +235,20 @@ uint32 DownloadDatabase::GetNextDownloadId() {
       "SELECT max(id) FROM downloads"));
   bool result = select_max_id.Step();
   DCHECK(result);
-  // If there are zero records in the downloads table, then max(id) will return
-  // 0 = kInvalidId, so GetNextDownloadId() will set *id = kInvalidId + 1.
-  // If there is at least one record but all of the |id|s are <= kInvalidId,
-  // then max(id) will return <= kInvalidId, so GetNextDownloadId should return
-  // kInvalidId + 1. Note that any records with |id <= kInvalidId| will be
-  // dropped in QueryDownloads()
+  // If there are zero records in the downloads table, then max(id) will
+  // return 0 = kInvalidDownloadId, so GetNextDownloadId() will set
+  // *id = kInvalidDownloadId + 1.
+  //
+  // If there is at least one record but all of the |id|s are
+  // <= kInvalidDownloadId, then max(id) will return <= kInvalidDownloadId,
+  // so GetNextDownloadId() should return kInvalidDownloadId + 1.
+  //
+  // Note that any records with |id <= kInvalidDownloadId| will be dropped in
+  // QueryDownloads().
+  //
   // SQLITE doesn't have unsigned integers.
   return 1 + static_cast<uint32>(std::max(
-      static_cast<int64>(content::DownloadItem::kInvalidId),
+      static_cast<int64>(kInvalidDownloadId),
       select_max_id.ColumnInt64(0)));
 }
 
@@ -350,8 +256,7 @@ bool DownloadDatabase::DropDownloadTable() {
   return GetDB().Execute("DROP TABLE downloads");
 }
 
-void DownloadDatabase::QueryDownloads(
-    std::vector<DownloadRow>* results) {
+void DownloadDatabase::QueryDownloads(std::vector<DownloadRow>* results) {
   EnsureInProgressEntriesCleanedUp();
 
   results->clear();
@@ -375,24 +280,25 @@ void DownloadDatabase::QueryDownloads(
     // |id|s instead of casting them to very large uint32s, which would break
     // the max(id) logic in GetNextDownloadId().
     int64 signed_id = statement_main.ColumnInt64(column++);
-    info->id = static_cast<uint32>(signed_id);
+    info->id = IntToDownloadId(signed_id);
     info->current_path = ColumnFilePath(statement_main, column++);
     info->target_path = ColumnFilePath(statement_main, column++);
     info->mime_type = statement_main.ColumnString(column++);
     info->original_mime_type = statement_main.ColumnString(column++);
-    info->start_time = base::Time::FromInternalValue(
-        statement_main.ColumnInt64(column++));
+    info->start_time =
+        base::Time::FromInternalValue(statement_main.ColumnInt64(column++));
     info->received_bytes = statement_main.ColumnInt64(column++);
     info->total_bytes = statement_main.ColumnInt64(column++);
     int state = statement_main.ColumnInt(column++);
-    info->state = IntToState(state);
-    if (info->state == DownloadItem::MAX_DOWNLOAD_STATE)
+    info->state = IntToDownloadState(state);
+    if (info->state == DownloadState::INVALID)
       UMA_HISTOGRAM_COUNTS("Download.DatabaseInvalidState", state);
-    info->danger_type = IntToDangerType(statement_main.ColumnInt(column++));
-    info->interrupt_reason = static_cast<content::DownloadInterruptReason>(
-        statement_main.ColumnInt(column++));
-    info->end_time = base::Time::FromInternalValue(
-        statement_main.ColumnInt64(column++));
+    info->danger_type =
+        IntToDownloadDangerType(statement_main.ColumnInt(column++));
+    info->interrupt_reason =
+        IntToDownloadInterruptReason(statement_main.ColumnInt(column++));
+    info->end_time =
+        base::Time::FromInternalValue(statement_main.ColumnInt64(column++));
     info->opened = statement_main.ColumnInt(column++) != 0;
     info->referrer_url = GURL(statement_main.ColumnString(column++));
     info->by_ext_id = statement_main.ColumnString(column++);
@@ -403,15 +309,15 @@ void DownloadDatabase::QueryDownloads(
     // If the record is corrupted, note that and drop it.
     // http://crbug.com/251269
     DroppedReason dropped_reason = DROPPED_REASON_MAX;
-    if (signed_id <= static_cast<int64>(content::DownloadItem::kInvalidId)) {
+    if (signed_id <= static_cast<int64>(kInvalidDownloadId)) {
       // SQLITE doesn't have unsigned integers.
       dropped_reason = DROPPED_REASON_BAD_ID;
     } else if (!ids.insert(info->id).second) {
       dropped_reason = DROPPED_REASON_DUPLICATE_ID;
       NOTREACHED() << info->id;
-    } else if (info->state == DownloadItem::MAX_DOWNLOAD_STATE) {
+    } else if (info->state == DownloadState::INVALID) {
       dropped_reason = DROPPED_REASON_BAD_STATE;
-    } else if (info->danger_type == content::DOWNLOAD_DANGER_TYPE_MAX) {
+    } else if (info->danger_type == DownloadDangerType::INVALID) {
       dropped_reason = DROPPED_REASON_BAD_DANGER_TYPE;
     }
     if (dropped_reason != DROPPED_REASON_MAX) {
@@ -436,9 +342,9 @@ void DownloadDatabase::QueryDownloads(
     int64 signed_id = statement_chain.ColumnInt64(column++);
     int chain_index = statement_chain.ColumnInt(column++);
 
-    if (signed_id <= static_cast<int64>(content::DownloadItem::kInvalidId))
+    if (signed_id <= static_cast<int64>(kInvalidDownloadId))
       continue;
-    uint32 id = static_cast<uint32>(signed_id);
+    uint32 id = IntToDownloadId(signed_id);
 
     // Note that these DCHECKs may trip as a result of corrupted databases.
     // We have them because in debug builds the chances are higher there's
@@ -486,14 +392,12 @@ void DownloadDatabase::QueryDownloads(
 bool DownloadDatabase::UpdateDownload(const DownloadRow& data) {
   EnsureInProgressEntriesCleanedUp();
 
-  DCHECK_NE(content::DownloadItem::kInvalidId, data.id);
-  int state = StateToInt(data.state);
-  if (state == kStateInvalid) {
+  DCHECK_NE(kInvalidDownloadId, data.id);
+  if (data.state == DownloadState::INVALID) {
     NOTREACHED();
     return false;
   }
-  int danger_type = DangerTypeToInt(data.danger_type);
-  if (danger_type == kDangerTypeInvalid) {
+  if (data.danger_type == DownloadDangerType::INVALID) {
     NOTREACHED();
     return false;
   }
@@ -512,9 +416,10 @@ bool DownloadDatabase::UpdateDownload(const DownloadRow& data) {
   statement.BindString(column++, data.mime_type);
   statement.BindString(column++, data.original_mime_type);
   statement.BindInt64(column++, data.received_bytes);
-  statement.BindInt(column++, state);
-  statement.BindInt(column++, danger_type);
-  statement.BindInt(column++, static_cast<int>(data.interrupt_reason));
+  statement.BindInt(column++, DownloadStateToInt(data.state));
+  statement.BindInt(column++, DownloadDangerTypeToInt(data.danger_type));
+  statement.BindInt(column++,
+                    DownloadInterruptReasonToInt(data.interrupt_reason));
   statement.BindInt64(column++, data.end_time.ToInternalValue());
   statement.BindInt64(column++, data.total_bytes);
   statement.BindInt(column++, (data.opened ? 1 : 0));
@@ -522,7 +427,7 @@ bool DownloadDatabase::UpdateDownload(const DownloadRow& data) {
   statement.BindString(column++, data.by_ext_name);
   statement.BindString(column++, data.etag);
   statement.BindString(column++, data.last_modified);
-  statement.BindInt(column++, data.id);
+  statement.BindInt(column++, DownloadIdToInt(data.id));
 
   return statement.Run();
 }
@@ -533,27 +438,25 @@ void DownloadDatabase::EnsureInProgressEntriesCleanedUp() {
 
   sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "UPDATE downloads SET state=?, interrupt_reason=? WHERE state=?"));
-  statement.BindInt(0, kStateInterrupted);
-  statement.BindInt(1, content::DOWNLOAD_INTERRUPT_REASON_CRASH);
-  statement.BindInt(2, kStateInProgress);
+  statement.BindInt(0, DownloadStateToInt(DownloadState::INTERRUPTED));
+  statement.BindInt(1, DownloadInterruptReasonToInt(download_interrupt_crash_));
+  statement.BindInt(2, DownloadStateToInt(DownloadState::IN_PROGRESS));
 
   statement.Run();
   in_progress_entry_cleanup_completed_ = true;
 }
 
 bool DownloadDatabase::CreateDownload(const DownloadRow& info) {
-  DCHECK_NE(content::DownloadItem::kInvalidId, info.id);
+  DCHECK_NE(kInvalidDownloadId, info.id);
   EnsureInProgressEntriesCleanedUp();
 
   if (info.url_chain.empty())
     return false;
 
-  int state = StateToInt(info.state);
-  if (state == kStateInvalid)
+  if (info.state == DownloadState::INVALID)
     return false;
 
-  int danger_type = DangerTypeToInt(info.danger_type);
-  if (danger_type == kDangerTypeInvalid)
+  if (info.danger_type == DownloadDangerType::INVALID)
     return false;
 
   {
@@ -569,7 +472,7 @@ bool DownloadDatabase::CreateDownload(const DownloadRow& info) {
         "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"));
 
     int column = 0;
-    statement_insert.BindInt(column++, info.id);
+    statement_insert.BindInt(column++, DownloadIdToInt(info.id));
     BindFilePath(statement_insert, info.current_path, column++);
     BindFilePath(statement_insert, info.target_path, column++);
     statement_insert.BindString(column++, info.mime_type);
@@ -577,9 +480,11 @@ bool DownloadDatabase::CreateDownload(const DownloadRow& info) {
     statement_insert.BindInt64(column++, info.start_time.ToInternalValue());
     statement_insert.BindInt64(column++, info.received_bytes);
     statement_insert.BindInt64(column++, info.total_bytes);
-    statement_insert.BindInt(column++, state);
-    statement_insert.BindInt(column++, danger_type);
-    statement_insert.BindInt(column++, info.interrupt_reason);
+    statement_insert.BindInt(column++, DownloadStateToInt(info.state));
+    statement_insert.BindInt(column++,
+                             DownloadDangerTypeToInt(info.danger_type));
+    statement_insert.BindInt(
+        column++, DownloadInterruptReasonToInt(info.interrupt_reason));
     statement_insert.BindInt64(column++, info.end_time.ToInternalValue());
     statement_insert.BindInt(column++, info.opened ? 1 : 0);
     statement_insert.BindString(column++, info.referrer_url.spec());
diff --git a/chrome/browser/history/download_database.h b/components/history/core/browser/download_database.h
index 10ef59c..90d0b36 100644
--- a/chrome/browser/history/download_database.h
+++ b/components/history/core/browser/download_database.h
@@ -2,15 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_
-#define CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_
+#ifndef COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_
 
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/threading/platform_thread.h"
-#include "content/public/browser/download_item.h"
+#include "components/history/core/browser/download_types.h"
 #include "sql/meta_table.h"
 
 namespace sql {
@@ -25,14 +25,14 @@ struct DownloadRow;
 class DownloadDatabase {
  public:
   // Must call InitDownloadTable before using any other functions.
-  DownloadDatabase();
+  DownloadDatabase(DownloadInterruptReason download_interrupt_no_reason,
+                   DownloadInterruptReason download_interrupt_crash);
   virtual ~DownloadDatabase();
 
   uint32 GetNextDownloadId();
 
   // Get all the downloads from the database.
-  void QueryDownloads(
-      std::vector<DownloadRow>* results);
+  void QueryDownloads(std::vector<DownloadRow>* results);
 
   // Update the state of one download. Returns true if successful.
   // Does not update |url|, |start_time|; uses |id| only
@@ -84,28 +84,8 @@ class DownloadDatabase {
   bool DropDownloadTable();
 
  private:
-  FRIEND_TEST_ALL_PREFIXES(
-      HistoryBackendDBTest, ConfirmDownloadInProgressCleanup);
-
-  // Values used in the database for DownloadItem::State.
-  static const int kStateInvalid;
-  static const int kStateInProgress;
-  static const int kStateComplete;
-  static const int kStateCancelled;
-  static const int kStateBug140687;
-  static const int kStateInterrupted;
-
-  // Values used in the database for DownloadItem::DangerType
-  static const int kDangerTypeInvalid;
-  static const int kDangerTypeNotDangerous;
-  static const int kDangerTypeDangerousFile;
-  static const int kDangerTypeDangerousUrl;
-  static const int kDangerTypeDangerousContent;
-  static const int kDangerTypeMaybeDangerousContent;
-  static const int kDangerTypeUncommonContent;
-  static const int kDangerTypeUserValidated;
-  static const int kDangerTypeDangerousHost;
-  static const int kDangerTypePotentiallyUnwanted;
+  FRIEND_TEST_ALL_PREFIXES(HistoryBackendDBTest,
+                           ConfirmDownloadInProgressCleanup);
 
   // Fixes state of the download entries. Sometimes entries with IN_PROGRESS
   // state are not updated during browser shutdown (particularly when crashing).
@@ -118,13 +98,6 @@ class DownloadDatabase {
 
   void RemoveDownloadURLs(uint32 id);
 
-  // Utility functions for conversion between DownloadItem types
-  // and DownloadDatabase constants.
-  static int StateToInt(content::DownloadItem::DownloadState state);
-  static content::DownloadItem::DownloadState IntToState(int state);
-  static int DangerTypeToInt(content::DownloadDangerType danger_type);
-  static content::DownloadDangerType IntToDangerType(int danger_type);
-
   bool owning_thread_set_;
   base::PlatformThreadId owning_thread_;
 
@@ -135,9 +108,15 @@ class DownloadDatabase {
   // actually use the downloads database.
   bool in_progress_entry_cleanup_completed_;
 
+  // Those constants are defined in the embedder and injected into the
+  // database in the constructor. They represent the interrupt reason
+  // to use for respectively an undefined value and in case of a crash.
+  DownloadInterruptReason download_interrupt_no_reason_;
+  DownloadInterruptReason download_interrupt_crash_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadDatabase);
 };
 
 }  // namespace history
 
-#endif  // CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_
diff --git a/components/history/core/browser/download_row.cc b/components/history/core/browser/download_row.cc
new file mode 100644
index 0000000..ffd02e5
--- /dev/null
+++ b/components/history/core/browser/download_row.cc
@@ -0,0 +1,65 @@
+// 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 "components/history/core/browser/download_row.h"
+
+#include "components/history/core/browser/download_constants.h"
+
+namespace history {
+
+DownloadRow::DownloadRow()
+    : received_bytes(0),
+      total_bytes(0),
+      state(DownloadState::IN_PROGRESS),
+      danger_type(DownloadDangerType::NOT_DANGEROUS),
+      id(kInvalidDownloadId),
+      opened(false) {
+  // |interrupt_reason| is left undefined by this constructor as the value
+  // has no meaning unless |state| is equal to kStateInterrupted.
+}
+
+DownloadRow::DownloadRow(const base::FilePath& current_path,
+                         const base::FilePath& target_path,
+                         const std::vector<GURL>& url_chain,
+                         const GURL& referrer,
+                         const std::string& mime_type,
+                         const std::string& original_mime_type,
+                         const base::Time& start,
+                         const base::Time& end,
+                         const std::string& etag,
+                         const std::string& last_modified,
+                         int64 received,
+                         int64 total,
+                         DownloadState download_state,
+                         DownloadDangerType danger_type,
+                         DownloadInterruptReason interrupt_reason,
+                         DownloadId id,
+                         bool download_opened,
+                         const std::string& ext_id,
+                         const std::string& ext_name)
+    : current_path(current_path),
+      target_path(target_path),
+      url_chain(url_chain),
+      referrer_url(referrer),
+      mime_type(mime_type),
+      original_mime_type(original_mime_type),
+      start_time(start),
+      end_time(end),
+      etag(etag),
+      last_modified(last_modified),
+      received_bytes(received),
+      total_bytes(total),
+      state(download_state),
+      danger_type(danger_type),
+      interrupt_reason(interrupt_reason),
+      id(id),
+      opened(download_opened),
+      by_ext_id(ext_id),
+      by_ext_name(ext_name) {
+}
+
+DownloadRow::~DownloadRow() {
+}
+
+}  // namespace history
diff --git a/chrome/browser/history/download_row.h b/components/history/core/browser/download_row.h
index a0c094f..0553a67 100644
--- a/chrome/browser/history/download_row.h
+++ b/components/history/core/browser/download_row.h
@@ -2,17 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_HISTORY_DOWNLOAD_ROW_H_
-#define CHROME_BROWSER_HISTORY_DOWNLOAD_ROW_H_
+#ifndef COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_ROW_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_ROW_H_
 
 #include <string>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/time/time.h"
-#include "content/public/browser/download_danger_type.h"
-#include "content/public/browser/download_interrupt_reasons.h"
-#include "content/public/browser/download_item.h"
+#include "components/history/core/browser/download_types.h"
 #include "url/gurl.h"
 
 namespace history {
@@ -22,26 +20,25 @@ namespace history {
 // DownloadDatabase through the HistoryService.
 struct DownloadRow {
   DownloadRow();
-  DownloadRow(
-      const base::FilePath& current_path,
-      const base::FilePath& target_path,
-      const std::vector<GURL>& url_chain,
-      const GURL& referrer,
-      const std::string& mime_type,
-      const std::string& original_mime_type,
-      const base::Time& start,
-      const base::Time& end,
-      const std::string& etag,
-      const std::string& last_modified,
-      int64 received,
-      int64 total,
-      content::DownloadItem::DownloadState download_state,
-      content::DownloadDangerType danger_type,
-      content::DownloadInterruptReason interrupt_reason,
-      uint32 id,
-      bool download_opened,
-      const std::string& ext_id,
-      const std::string& ext_name);
+  DownloadRow(const base::FilePath& current_path,
+              const base::FilePath& target_path,
+              const std::vector<GURL>& url_chain,
+              const GURL& referrer,
+              const std::string& mime_type,
+              const std::string& original_mime_type,
+              const base::Time& start,
+              const base::Time& end,
+              const std::string& etag,
+              const std::string& last_modified,
+              int64 received,
+              int64 total,
+              DownloadState download_state,
+              DownloadDangerType danger_type,
+              DownloadInterruptReason interrupt_reason,
+              DownloadId id,
+              bool download_opened,
+              const std::string& ext_id,
+              const std::string& ext_name);
   ~DownloadRow();
 
   // The current path to the download (potentially different from final if
@@ -86,17 +83,16 @@ struct DownloadRow {
   int64 total_bytes;
 
   // The current state of the download.
-  content::DownloadItem::DownloadState state;
+  DownloadState state;
 
   // Whether and how the download is dangerous.
-  content::DownloadDangerType danger_type;
+  DownloadDangerType danger_type;
 
-  // The reason the download was interrupted, if
-  // state == DownloadItem::INTERRUPTED
-  content::DownloadInterruptReason interrupt_reason;
+  // The reason the download was interrupted, if state == kStateInterrupted.
+  DownloadInterruptReason interrupt_reason;
 
   // The id of the download in the database. Is not changed by UpdateDownload().
-  uint32 id;
+  DownloadId id;
 
   // Whether this download has ever been opened from the browser.
   bool opened;
@@ -108,4 +104,4 @@ struct DownloadRow {
 
 }  // namespace history
 
-#endif  // CHROME_BROWSER_HISTORY_DOWNLOAD_ROW_H_
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_ROW_H_
diff --git a/components/history/core/browser/download_types.cc b/components/history/core/browser/download_types.cc
new file mode 100644
index 0000000..ccc2018
--- /dev/null
+++ b/components/history/core/browser/download_types.cc
@@ -0,0 +1,129 @@
+// 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_types.h"
+
+#include <ostream>
+
+#include "base/logging.h"
+#include "components/history/core/browser/download_constants.h"
+
+namespace history {
+
+DownloadState IntToDownloadState(int state) {
+  switch (static_cast<DownloadState>(state)) {
+    case DownloadState::IN_PROGRESS:
+    case DownloadState::COMPLETE:
+    case DownloadState::CANCELLED:
+    case DownloadState::INTERRUPTED:
+      return static_cast<DownloadState>(state);
+
+    case DownloadState::INVALID:
+    case DownloadState::BUG_140687:
+      NOTREACHED();
+      return DownloadState::INVALID;
+  }
+  NOTREACHED();
+  return DownloadState::INVALID;
+}
+
+int DownloadStateToInt(DownloadState state) {
+  DCHECK_NE(state, DownloadState::INVALID);
+  return static_cast<int>(state);
+}
+
+std::ostream& operator<<(std::ostream& stream, DownloadState state) {
+  switch (state) {
+    case DownloadState::INVALID:
+      return stream << "history::DownloadState::COMPLETE";
+    case DownloadState::IN_PROGRESS:
+      return stream << "history::DownloadState::IN_PROGRESS";
+    case DownloadState::COMPLETE:
+      return stream << "history::DownloadState::COMPLETE";
+    case DownloadState::CANCELLED:
+      return stream << "history::DownloadState::CANCELLED";
+    case DownloadState::BUG_140687:
+      return stream << "history::DownloadState::BUG_140687";
+    case DownloadState::INTERRUPTED:
+      return stream << "history::DownloadState::INTERRUPTED";
+  }
+  NOTREACHED();
+  return stream;
+}
+
+DownloadDangerType IntToDownloadDangerType(int danger_type) {
+  switch (static_cast<DownloadDangerType>(danger_type)) {
+    case DownloadDangerType::NOT_DANGEROUS:
+    case DownloadDangerType::DANGEROUS_FILE:
+    case DownloadDangerType::DANGEROUS_URL:
+    case DownloadDangerType::DANGEROUS_CONTENT:
+    case DownloadDangerType::MAYBE_DANGEROUS_CONTENT:
+    case DownloadDangerType::UNCOMMON_CONTENT:
+    case DownloadDangerType::USER_VALIDATED:
+    case DownloadDangerType::DANGEROUS_HOST:
+    case DownloadDangerType::POTENTIALLY_UNWANTED:
+      return static_cast<DownloadDangerType>(danger_type);
+
+    case DownloadDangerType::INVALID:
+      NOTREACHED();
+      return DownloadDangerType::INVALID;
+  }
+  NOTREACHED();
+  return DownloadDangerType::INVALID;
+}
+
+int DownloadDangerTypeToInt(DownloadDangerType danger_type) {
+  DCHECK_NE(danger_type, DownloadDangerType::INVALID);
+  return static_cast<int>(danger_type);
+}
+
+std::ostream& operator<<(std::ostream& stream, DownloadDangerType danger_type) {
+  switch (danger_type) {
+    case DownloadDangerType::INVALID:
+      return stream << "history::DownloadDangerType::INVALID";
+    case DownloadDangerType::NOT_DANGEROUS:
+      return stream << "history::DownloadDangerType::NOT_DANGEROUS";
+    case DownloadDangerType::DANGEROUS_FILE:
+      return stream << "history::DownloadDangerType::DANGEROUS_FILE";
+    case DownloadDangerType::DANGEROUS_URL:
+      return stream << "history::DownloadDangerType::DANGEROUS_URL";
+    case DownloadDangerType::DANGEROUS_CONTENT:
+      return stream << "history::DownloadDangerType::DANGEROUS_CONTENT";
+    case DownloadDangerType::MAYBE_DANGEROUS_CONTENT:
+      return stream << "history::DownloadDangerType::MAYBE_DANGEROUS_CONTENT";
+    case DownloadDangerType::UNCOMMON_CONTENT:
+      return stream << "history::DownloadDangerType::UNCOMMON_CONTENT";
+    case DownloadDangerType::USER_VALIDATED:
+      return stream << "history::DownloadDangerType::USER_VALIDATED";
+    case DownloadDangerType::DANGEROUS_HOST:
+      return stream << "history::DownloadDangerType::DANGEROUS_HOST";
+    case DownloadDangerType::POTENTIALLY_UNWANTED:
+      return stream << "history::DownloadDangerType::POTENTIALLY_UNWANTED";
+  }
+  NOTREACHED();
+  return stream;
+}
+
+DownloadInterruptReason IntToDownloadInterruptReason(int interrupt_reason) {
+  return static_cast<DownloadInterruptReason>(interrupt_reason);
+}
+
+int DownloadInterruptReasonToInt(DownloadInterruptReason interrupt_reason) {
+  return static_cast<int>(interrupt_reason);
+}
+
+const DownloadId kInvalidDownloadId = 0;
+
+DownloadId IntToDownloadId(int64_t id) {
+  DCHECK_GE(id, static_cast<int64_t>(0));
+  DCHECK_NE(id, static_cast<int64_t>(kInvalidDownloadId));
+  return static_cast<DownloadId>(id);
+}
+
+int64_t DownloadIdToInt(DownloadId id) {
+  DCHECK_NE(id, kInvalidDownloadId);
+  return static_cast<int64_t>(id);
+}
+
+}  // namespace history
diff --git a/components/history/core/browser/download_types.h b/components/history/core/browser/download_types.h
new file mode 100644
index 0000000..1c6650d
--- /dev/null
+++ b/components/history/core/browser/download_types.h
@@ -0,0 +1,62 @@
+// 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.
+
+#ifndef COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_TYPES_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_TYPES_H_
+
+#include <stdint.h>
+#include <iosfwd>
+
+namespace history {
+
+// DownloadState represents the state of a DownloadRow saved into the
+// DownloadDatabase. The values must not be changed as they are saved
+// to disk in the database.
+enum class DownloadState;
+
+// Utility functions to convert between int and DownloadState for
+// serialization to the download database.
+DownloadState IntToDownloadState(int state);
+int DownloadStateToInt(DownloadState state);
+
+// operator<< is defined to allow DownloadState to work with DCHECK/EXPECT.
+std::ostream& operator<<(std::ostream& stream, DownloadState state);
+
+// DownloadDangerType represents the danger of a DownloadRow into the
+// DownloadDatabase. The values must not be changed as they are saved
+// to disk in the database.
+enum class DownloadDangerType;
+
+// Utility functions to convert between int and DownloadDangerType for
+// serialization to the download database.
+DownloadDangerType IntToDownloadDangerType(int danger_type);
+int DownloadDangerTypeToInt(DownloadDangerType danger_type);
+
+// operator<< is defined to allow DownloadDangerType to work with DCHECK/EXPECT.
+std::ostream& operator<<(std::ostream& stream, DownloadDangerType danger_type);
+
+// DownloadInterruptReason represents the reason a download was interrupted
+// of a DownloadRow into the DownloadDatabase. The values must not be changed
+// as they are saved to disk in the database. They have no meaning for the
+// history component.
+typedef int32_t DownloadInterruptReason;
+
+// Utility functions to convert between int and DownloadInterruptReason for
+// serialization to the download database.
+DownloadInterruptReason IntToDownloadInterruptReason(int interrupt_reason);
+int DownloadInterruptReasonToInt(DownloadInterruptReason interrupt_reason);
+
+// DownloadId represents the id of a DownloadRow into the DownloadDatabase.
+// The value is controlled by the embedder except for the reserved id
+// kInvalidDownloadId.
+typedef uint32_t DownloadId;
+
+// Utility functions to convert between int and DownloadId for
+// serialization to the download database.
+DownloadId IntToDownloadId(int64_t id);
+int64_t DownloadIdToInt(DownloadId id);
+
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_TYPES_H_