Remove dependency on Profile from HistoryService

Introduce an abstract interface history::VisitDelegate to abstract
visitedlink::VisitedLinkMaster from visitedlink component that has
a dependency on //content and thus cannot be used on iOS.

Provides an implementation of history::VisitDelegate that forward
to visitedlink::VisitedLinkMaster and inject it into HistoryService
via the HistoryServiceFactory.

Remove dependency on visitedlink component from HistoryService and
HistoryBackend.

Fix file that dependended on the forward-declaration of Profile
from history_service.h

Cleanup //chrome/browser/history/DEPS.

Fix typos and some style issues.

BUG=453790

Review URL: https://codereview.chromium.org/872313005

Cr-Commit-Position: refs/heads/master@{#316836}

22 files changed, 334 insertions, 150 deletions

diff --git a/chrome/browser/autocomplete/shortcuts_provider_unittest.cc b/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
index e5546bd..b2e4da3 100644
--- a/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
+++ b/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
@@ -314,6 +314,7 @@ void ShortcutsProviderTest::TearDown() {
   // Run all pending tasks or else some threads hold on to the message loop
   // and prevent it from being deleted.
   message_loop_.RunUntilIdle();
+  profile_.DestroyHistoryService();
   provider_ = NULL;
 }
 
diff --git a/chrome/browser/history/DEPS b/chrome/browser/history/DEPS
index 030f20e..7dfc95c 100644
--- a/chrome/browser/history/DEPS
+++ b/chrome/browser/history/DEPS
@@ -29,8 +29,6 @@ include_rules = [
   "!chrome/browser/ui/browser_finder.h",
   "!components/bookmarks/browser/bookmark_utils.h",
   "!components/dom_distiller/core/url_constants.h",
-  "!components/visitedlink/browser/visitedlink_delegate.h",
-  "!components/visitedlink/browser/visitedlink_master.h",
 ]
 
 specific_include_rules = {
@@ -54,6 +52,11 @@ specific_include_rules = {
     "+components/bookmarks/browser",
     "+components/keyed_service/content",
   ],
+  # Those files will move to //components/history/content/browser and thus
+  # can depend on //content even indirectly.
+  'content_.*\.(cc|h)': [
+    "+components/visitedlink/browser",
+  ],
   # TODO(sdefresne): Bring this list to zero.
   #
   # Do not add to the list of temporarily-allowed dependencies below,
diff --git a/chrome/browser/history/content_visit_delegate.cc b/chrome/browser/history/content_visit_delegate.cc
new file mode 100644
index 0000000..6bd3935
--- /dev/null
+++ b/chrome/browser/history/content_visit_delegate.cc
@@ -0,0 +1,121 @@
+// 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 "chrome/browser/history/content_visit_delegate.h"
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "chrome/browser/history/history_backend.h"
+#include "chrome/browser/history/history_service.h"
+#include "components/history/core/browser/history_database.h"
+#include "components/history/core/browser/history_db_task.h"
+#include "components/visitedlink/browser/visitedlink_master.h"
+#include "url/gurl.h"
+
+namespace {
+
+// URLIterator from std::vector<GURL>
+class URLIteratorFromURLs : public visitedlink::VisitedLinkMaster::URLIterator {
+ public:
+  explicit URLIteratorFromURLs(const std::vector<GURL>& urls)
+      : itr_(urls.begin()), end_(urls.end()) {}
+
+  // visitedlink::VisitedLinkMaster::URLIterator implementation.
+  const GURL& NextURL() override { return *(itr_++); }
+  bool HasNextURL() const override { return itr_ != end_; }
+
+ private:
+  std::vector<GURL>::const_iterator itr_;
+  std::vector<GURL>::const_iterator end_;
+
+  DISALLOW_COPY_AND_ASSIGN(URLIteratorFromURLs);
+};
+
+// IterateUrlsDBTask bridge HistoryBackend::URLEnumerator to
+// visitedlink::VisitedLinkDelegate::URLEnumerator.
+class IterateUrlsDBTask : public history::HistoryDBTask {
+ public:
+  explicit IterateUrlsDBTask(const scoped_refptr<
+      visitedlink::VisitedLinkDelegate::URLEnumerator>& enumerator);
+  ~IterateUrlsDBTask() override;
+
+ private:
+  // Implementation of history::HistoryDBTask.
+  bool RunOnDBThread(history::HistoryBackend* backend,
+                     history::HistoryDatabase* db) override;
+  void DoneRunOnMainThread() override;
+
+  scoped_refptr<visitedlink::VisitedLinkDelegate::URLEnumerator> enumerator_;
+
+  DISALLOW_COPY_AND_ASSIGN(IterateUrlsDBTask);
+};
+
+IterateUrlsDBTask::IterateUrlsDBTask(const scoped_refptr<
+    visitedlink::VisitedLinkDelegate::URLEnumerator>& enumerator)
+    : enumerator_(enumerator) {
+}
+
+IterateUrlsDBTask::~IterateUrlsDBTask() {
+}
+
+bool IterateUrlsDBTask::RunOnDBThread(history::HistoryBackend* backend,
+                                      history::HistoryDatabase* db) {
+  bool success = false;
+  if (db) {
+    history::HistoryDatabase::URLEnumerator iter;
+    if (db->InitURLEnumeratorForEverything(&iter)) {
+      history::URLRow row;
+      while (iter.GetNextURL(&row))
+        enumerator_->OnURL(row.url());
+      success = true;
+    }
+  }
+  enumerator_->OnComplete(success);
+  return true;
+}
+
+void IterateUrlsDBTask::DoneRunOnMainThread() {
+}
+
+}  // namespace
+
+ContentVisitDelegate::ContentVisitDelegate(
+    content::BrowserContext* browser_context)
+    : history_service_(nullptr),
+      visitedlink_master_(
+          new visitedlink::VisitedLinkMaster(browser_context, this, true)) {
+}
+
+ContentVisitDelegate::~ContentVisitDelegate() {
+}
+
+bool ContentVisitDelegate::Init(HistoryService* history_service) {
+  DCHECK(history_service);
+  history_service_ = history_service;
+  return visitedlink_master_->Init();
+}
+
+void ContentVisitDelegate::AddURL(const GURL& url) {
+  visitedlink_master_->AddURL(url);
+}
+
+void ContentVisitDelegate::AddURLs(const std::vector<GURL>& urls) {
+  visitedlink_master_->AddURLs(urls);
+}
+
+void ContentVisitDelegate::DeleteURLs(const std::vector<GURL>& urls) {
+  URLIteratorFromURLs iterator(urls);
+  visitedlink_master_->DeleteURLs(&iterator);
+}
+
+void ContentVisitDelegate::DeleteAllURLs() {
+  visitedlink_master_->DeleteAllURLs();
+}
+
+void ContentVisitDelegate::RebuildTable(
+    const scoped_refptr<URLEnumerator>& enumerator) {
+  DCHECK(history_service_);
+  scoped_ptr<history::HistoryDBTask> task(new IterateUrlsDBTask(enumerator));
+  history_service_->ScheduleDBTask(task.Pass(), &task_tracker_);
+}
diff --git a/chrome/browser/history/content_visit_delegate.h b/chrome/browser/history/content_visit_delegate.h
new file mode 100644
index 0000000..df98c72
--- /dev/null
+++ b/chrome/browser/history/content_visit_delegate.h
@@ -0,0 +1,51 @@
+// 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 CHROME_BROWSER_HISTORY_CONTENT_VISIT_DELEGATE_H_
+#define CHROME_BROWSER_HISTORY_CONTENT_VISIT_DELEGATE_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/task/cancelable_task_tracker.h"
+#include "components/history/core/browser/visit_delegate.h"
+#include "components/visitedlink/browser/visitedlink_delegate.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace visitedlink {
+class VisitedLinkMaster;
+}
+
+// ContentVisitDelegate bridge history::VisitDelegate events to
+// visitedlink::VisitedLinkMaster.
+class ContentVisitDelegate : public history::VisitDelegate,
+                             public visitedlink::VisitedLinkDelegate {
+ public:
+  explicit ContentVisitDelegate(content::BrowserContext* browser_context);
+  ~ContentVisitDelegate() override;
+
+ private:
+  // Implementation of history::VisitDelegate.
+  bool Init(HistoryService* history_service) override;
+  void AddURL(const GURL& url) override;
+  void AddURLs(const std::vector<GURL>& urls) override;
+  void DeleteURLs(const std::vector<GURL>& urls) override;
+  void DeleteAllURLs() override;
+
+  // Implementation of visitedlink::VisitedLinkDelegate.
+  void RebuildTable(const scoped_refptr<
+      visitedlink::VisitedLinkDelegate::URLEnumerator>& enumerator) override;
+
+  HistoryService* history_service_;  // Weak.
+  scoped_ptr<visitedlink::VisitedLinkMaster> visitedlink_master_;
+  base::CancelableTaskTracker task_tracker_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentVisitDelegate);
+};
+
+#endif  // CHROME_BROWSER_HISTORY_CONTENT_VISIT_DELEGATE_H_
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 26c7133..0bbbf400 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -172,8 +172,7 @@ bool QueuedHistoryDBTask::is_canceled() {
   return is_canceled_.Run();
 }
 
-bool QueuedHistoryDBTask::Run(HistoryBackend* backend,
-                                        HistoryDatabase* db) {
+bool QueuedHistoryDBTask::Run(HistoryBackend* backend, HistoryDatabase* db) {
   return task_->RunOnDBThread(backend, db);
 }
 
@@ -924,23 +923,6 @@ void HistoryBackend::AddPageNoVisitForBookmark(const GURL& url,
   db_->AddURL(url_info);
 }
 
-void HistoryBackend::IterateURLs(
-    const scoped_refptr<visitedlink::VisitedLinkDelegate::URLEnumerator>&
-    iterator) {
-  if (db_) {
-    HistoryDatabase::URLEnumerator e;
-    if (db_->InitURLEnumeratorForEverything(&e)) {
-      URLRow info;
-      while (e.GetNextURL(&info)) {
-        iterator->OnURL(info.url());
-      }
-      iterator->OnComplete(true);  // Success.
-      return;
-    }
-  }
-  iterator->OnComplete(false);  // Failure.
-}
-
 bool HistoryBackend::GetAllTypedURLs(URLRows* urls) {
   if (db_)
     return db_->GetAllTypedUrls(urls);
diff --git a/chrome/browser/history/history_backend.h b/chrome/browser/history/history_backend.h
index 0750ac7..75a0121 100644
--- a/chrome/browser/history/history_backend.h
+++ b/chrome/browser/history/history_backend.h
@@ -25,7 +25,6 @@
 #include "components/history/core/browser/keyword_id.h"
 #include "components/history/core/browser/thumbnail_database.h"
 #include "components/history/core/browser/visit_tracker.h"
-#include "components/visitedlink/browser/visitedlink_delegate.h"
 #include "sql/init_status.h"
 
 #if defined(OS_ANDROID)
@@ -220,9 +219,6 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
   void ScheduleAutocomplete(const base::Callback<
       void(history::HistoryBackend*, history::URLDatabase*)>& callback);
 
-  void IterateURLs(
-      const scoped_refptr<visitedlink::VisitedLinkDelegate::URLEnumerator>&
-          enumerator);
   void QueryURL(const GURL& url,
                 bool want_visits,
                 QueryURLResult* query_url_result);
diff --git a/chrome/browser/history/history_backend_unittest.cc b/chrome/browser/history/history_backend_unittest.cc
index 6f3a46d..9eeca2a 100644
--- a/chrome/browser/history/history_backend_unittest.cc
+++ b/chrome/browser/history/history_backend_unittest.cc
@@ -22,6 +22,7 @@
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/history/content_visit_delegate.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
@@ -3041,8 +3042,8 @@ TEST_F(HistoryBackendTest, RemoveNotification) {
   GURL url("http://www.google.com");
   HistoryClientMock history_client;
   history_client.AddBookmark(url);
-  scoped_ptr<HistoryService> service(
-      new HistoryService(&history_client, profile.get()));
+  scoped_ptr<HistoryService> service(new HistoryService(
+      &history_client, scoped_ptr<history::VisitDelegate>()));
   EXPECT_TRUE(
       service->Init(profile->GetPrefs()->GetString(prefs::kAcceptLanguages),
                     TestHistoryDatabaseParamsForPath(profile->GetPath())));
diff --git a/chrome/browser/history/history_service.cc b/chrome/browser/history/history_service.cc
index 61d4cdf..2e25db8 100644
--- a/chrome/browser/history/history_service.cc
+++ b/chrome/browser/history/history_service.cc
@@ -42,12 +42,10 @@
 #include "components/history/core/browser/in_memory_database.h"
 #include "components/history/core/browser/keyword_search_term.h"
 #include "components/history/core/browser/visit_database.h"
+#include "components/history/core/browser/visit_delegate.h"
 #include "components/history/core/browser/visit_filter.h"
 #include "components/history/core/browser/web_history_service.h"
 #include "components/history/core/common/thumbnail_score.h"
-#include "components/visitedlink/browser/visitedlink_master.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/download_item.h"
 #include "sync/api/sync_error_factory.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
@@ -82,26 +80,6 @@ void RunWithVisibleVisitCountToHostResult(
   callback.Run(result->success, result->count, result->first_visit);
 }
 
-// Extract history::URLRows into GURLs for VisitedLinkMaster.
-class URLIteratorFromURLRows
-    : public visitedlink::VisitedLinkMaster::URLIterator {
- public:
-  explicit URLIteratorFromURLRows(const history::URLRows& url_rows)
-      : itr_(url_rows.begin()),
-        end_(url_rows.end()) {
-  }
-
-  const GURL& NextURL() override { return (itr_++)->url(); }
-
-  bool HasNextURL() const override { return itr_ != end_; }
-
- private:
-  history::URLRows::const_iterator itr_;
-  history::URLRows::const_iterator end_;
-
-  DISALLOW_COPY_AND_ASSIGN(URLIteratorFromURLRows);
-};
-
 // Callback from WebHistoryService::ExpireWebHistory().
 void ExpireWebHistoryComplete(bool success) {
   // Ignore the result.
@@ -214,18 +192,18 @@ class HistoryService::BackendDelegate : public HistoryBackend::Delegate {
 // history thread.
 HistoryService::HistoryService()
     : thread_(new base::Thread(kHistoryThreadName)),
-      history_client_(NULL),
+      history_client_(nullptr),
       backend_loaded_(false),
       no_db_(false),
       weak_ptr_factory_(this) {
 }
 
 HistoryService::HistoryService(
-    history::HistoryClient* history_client, Profile* profile)
+    history::HistoryClient* history_client,
+    scoped_ptr<history::VisitDelegate> visit_delegate)
     : thread_(new base::Thread(kHistoryThreadName)),
+      visit_delegate_(visit_delegate.Pass()),
       history_client_(history_client),
-      visitedlink_master_(new visitedlink::VisitedLinkMaster(
-          profile, this, true)),
       backend_loaded_(false),
       no_db_(false),
       weak_ptr_factory_(this) {
@@ -253,7 +231,7 @@ void HistoryService::ClearCachedDataForContextID(
 
 history::URLDatabase* HistoryService::InMemoryDatabase() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  return in_memory_backend_ ? in_memory_backend_->db() : NULL;
+  return in_memory_backend_ ? in_memory_backend_->db() : nullptr;
 }
 
 bool HistoryService::GetTypedCountForURL(const GURL& url, int* typed_count) {
@@ -404,7 +382,7 @@ void HistoryService::AddPage(const GURL& url,
                              history::VisitSource visit_source) {
   DCHECK(thread_checker_.CalledOnValidThread());
   AddPage(
-      history::HistoryAddPageArgs(url, time, NULL, 0, GURL(),
+      history::HistoryAddPageArgs(url, time, nullptr, 0, GURL(),
                                   history::RedirectList(),
                                   ui::PAGE_TRANSITION_LINK,
                                   visit_source, false));
@@ -421,19 +399,17 @@ void HistoryService::AddPage(const history::HistoryAddPageArgs& add_page_args) {
   if (!CanAddURL(add_page_args.url))
     return;
 
-  // Add link & all redirects to visited link list.
-  if (visitedlink_master_) {
-    visitedlink_master_->AddURL(add_page_args.url);
-
+  // Inform VisitedDelegate of all links and redirects.
+  if (visit_delegate_) {
     if (!add_page_args.redirects.empty()) {
-      // We should not be asked to add a page in the middle of a redirect chain.
-      DCHECK_EQ(add_page_args.url,
-                add_page_args.redirects[add_page_args.redirects.size() - 1]);
-
-      // We need the !redirects.empty() condition above since size_t is unsigned
-      // and will wrap around when we subtract one from a 0 size.
-      for (size_t i = 0; i < add_page_args.redirects.size() - 1; i++)
-        visitedlink_master_->AddURL(add_page_args.redirects[i]);
+      // We should not be asked to add a page in the middle of a redirect chain,
+      // and thus add_page_args.url should be the last element in the array
+      // add_page_args.redirects which mean we can use VisitDelegate::AddURLs()
+      // with the whole array.
+      DCHECK_EQ(add_page_args.url, add_page_args.redirects.back());
+      visit_delegate_->AddURLs(add_page_args.redirects);
+    } else {
+      visit_delegate_->AddURL(add_page_args.url);
     }
   }
 
@@ -487,9 +463,9 @@ void HistoryService::AddPageWithDetails(const GURL& url,
   if (!CanAddURL(url))
     return;
 
-  // Add to the visited links system.
-  if (visitedlink_master_)
-    visitedlink_master_->AddURL(url);
+  // Inform VisitDelegate of the URL.
+  if (visit_delegate_)
+    visit_delegate_->AddURL(url);
 
   history::URLRow row(url);
   row.set_title(title);
@@ -510,15 +486,14 @@ void HistoryService::AddPagesWithDetails(const history::URLRows& info,
                                          history::VisitSource visit_source) {
   DCHECK(thread_) << "History service being called after cleanup";
   DCHECK(thread_checker_.CalledOnValidThread());
-  // Add to the visited links system.
-  if (visitedlink_master_) {
+
+  // Inform the VisitDelegate of the URLs
+  if (!info.empty() && visit_delegate_) {
     std::vector<GURL> urls;
     urls.reserve(info.size());
-    for (history::URLRows::const_iterator i = info.begin(); i != info.end();
-         ++i)
-      urls.push_back(i->url());
-
-    visitedlink_master_->AddURLs(urls);
+    for (const auto& row : info)
+      urls.push_back(row.url());
+    visit_delegate_->AddURLs(urls);
   }
 
   ScheduleTask(PRIORITY_NORMAL,
@@ -750,7 +725,7 @@ void HistoryService::QueryDownloads(
   DCHECK(thread_checker_.CalledOnValidThread());
   std::vector<history::DownloadRow>* rows =
     new std::vector<history::DownloadRow>();
-  scoped_ptr<std::vector<history::DownloadRow> > scoped_rows(rows);
+  scoped_ptr<std::vector<history::DownloadRow>> scoped_rows(rows);
   // Beware! The first Bind() does not simply |scoped_rows.get()| because
   // base::Passed(&scoped_rows) nullifies |scoped_rows|, and compilers do not
   // guarantee that the first Bind's arguments are evaluated before the second
@@ -936,26 +911,18 @@ void HistoryService::Cleanup() {
     ScheduleTask(PRIORITY_NORMAL, closing_task);
     closing_task.Reset();
     HistoryBackend* raw_ptr = history_backend_.get();
-    history_backend_ = NULL;
+    history_backend_ = nullptr;
     thread_->message_loop()->ReleaseSoon(FROM_HERE, raw_ptr);
   }
 
   // Delete the thread, which joins with the background thread. We defensively
-  // NULL the pointer before deleting it in case somebody tries to use it
+  // nullptr the pointer before deleting it in case somebody tries to use it
   // during shutdown, but this shouldn't happen.
   base::Thread* thread = thread_;
-  thread_ = NULL;
+  thread_ = nullptr;
   delete thread;
 }
 
-void HistoryService::RebuildTable(
-    const scoped_refptr<URLEnumerator>& enumerator) {
-  DCHECK(thread_) << "History service being called after cleanup";
-  DCHECK(thread_checker_.CalledOnValidThread());
-  ScheduleTask(PRIORITY_NORMAL, base::Bind(&HistoryBackend::IterateURLs,
-                                           history_backend_.get(), enumerator));
-}
-
 bool HistoryService::Init(
     bool no_db,
     const std::string& languages,
@@ -991,10 +958,8 @@ bool HistoryService::Init(
                base::Bind(&HistoryBackend::Init, history_backend_.get(),
                           languages, no_db_, history_database_params));
 
-  if (visitedlink_master_) {
-    bool result = visitedlink_master_->Init();
-    DCHECK(result);
-  }
+  if (visit_delegate_ && !visit_delegate_->Init(this))
+    return false;
 
   return true;
 }
@@ -1220,21 +1185,23 @@ void HistoryService::NotifyURLsDeleted(bool all_history,
   if (!thread_)
     return;
 
-  // Update the visited link system for deleted URLs. We will update the
-  // visited link system for added URLs as soon as we get the add
-  // notification (we don't have to wait for the backend, which allows us to
-  // be faster to update the state).
+  // Inform the VisitDelegate of the deleted URLs. We will inform the delegate
+  // of added URLs as soon as we get the add notification (we don't have to wait
+  // for the backend, which allows us to be faster to update the state).
   //
   // For deleted URLs, we don't typically know what will be deleted since
   // delete notifications are by time. We would also like to be more
   // respectful of privacy and never tell the user something is gone when it
   // isn't. Therefore, we update the delete URLs after the fact.
-  if (visitedlink_master_) {
+  if (visit_delegate_) {
     if (all_history) {
-      visitedlink_master_->DeleteAllURLs();
+      visit_delegate_->DeleteAllURLs();
     } else {
-      URLIteratorFromURLRows iterator(deleted_rows);
-      visitedlink_master_->DeleteURLs(&iterator);
+      std::vector<GURL> urls;
+      urls.reserve(deleted_rows.size());
+      for (const auto& row : deleted_rows)
+        urls.push_back(row.url());
+      visit_delegate_->DeleteURLs(urls);
     }
   }
 
diff --git a/chrome/browser/history/history_service.h b/chrome/browser/history/history_service.h
index 8b2b4b0..55b8858 100644
--- a/chrome/browser/history/history_service.h
+++ b/chrome/browser/history/history_service.h
@@ -29,7 +29,6 @@
 #include "components/favicon_base/favicon_usage_data.h"
 #include "components/history/core/browser/keyword_id.h"
 #include "components/keyed_service/core/keyed_service.h"
-#include "components/visitedlink/browser/visitedlink_delegate.h"
 #include "sql/init_status.h"
 #include "sync/api/syncable_service.h"
 #include "ui/base/page_transition_types.h"
@@ -39,9 +38,7 @@ class AndroidHistoryProviderService;
 #endif
 
 class GURL;
-class HistoryService;
 class PageUsageRequest;
-class Profile;
 class SkBitmap;
 
 namespace base {
@@ -49,10 +46,6 @@ class FilePath;
 class Thread;
 }
 
-namespace visitedlink {
-class VisitedLinkMaster;
-}
-
 namespace history {
 
 struct DownloadRow;
@@ -71,6 +64,7 @@ class InMemoryURLIndexTest;
 struct KeywordSearchTermVisit;
 class PageUsageData;
 class URLDatabase;
+class VisitDelegate;
 class VisitFilter;
 class WebHistoryService;
 
@@ -81,19 +75,18 @@ class WebHistoryService;
 //
 // This service is thread safe. Each request callback is invoked in the
 // thread that made the request.
-class HistoryService : public syncer::SyncableService,
-                       public KeyedService,
-                       public visitedlink::VisitedLinkDelegate {
+class HistoryService : public syncer::SyncableService, public KeyedService {
  public:
   // Miscellaneous commonly-used types.
   typedef std::vector<history::PageUsageData*> PageUsageDataList;
 
-  // Must call Init after construction. The |history::HistoryClient| object
-  // must be valid for the whole lifetime of |HistoryService|.
-  HistoryService(history::HistoryClient* client, Profile* profile);
-  // The empty constructor is provided only for testing.
+  // Must call Init after construction. The empty constructor provided only for
+  // unit tests. When using the full constructor, |history_client| and |profile|
+  // should only be null during testing, while |visit_delegate| may be null if
+  // the embedder use another way to track visited links.
   HistoryService();
-
+  HistoryService(history::HistoryClient* history_client,
+                 scoped_ptr<history::VisitDelegate> visit_delegate);
   ~HistoryService() override;
 
   // Initializes the history service, returning true on success. On false, do
@@ -119,7 +112,7 @@ class HistoryService : public syncer::SyncableService,
   void ClearCachedDataForContextID(history::ContextID context_id);
 
   // Triggers the backend to load if it hasn't already, and then returns the
-  // in-memory URL database. The returned pointer MAY BE NULL if the in-memory
+  // in-memory URL database. The returned pointer may be null if the in-memory
   // database has not been loaded yet. This pointer is owned by the history
   // system. Callers should not store or cache this value.
   //
@@ -161,7 +154,7 @@ class HistoryService : public syncer::SyncableService,
   // are only unique inside a given context, so we need that to differentiate
   // them.
   //
-  // The context/page ids can be NULL if there is no meaningful tracking
+  // The context/page ids can be null if there is no meaningful tracking
   // information that can be performed on the given URL. The 'nav_entry_id'
   // should be the unique ID of the current navigation entry in the given
   // process.
@@ -393,9 +386,8 @@ class HistoryService : public syncer::SyncableService,
 
   // Implemented by the caller of 'QueryDownloads' below, and is called when the
   // history service has retrieved a list of all download state. The call
-  typedef base::Callback<void(
-      scoped_ptr<std::vector<history::DownloadRow> >)>
-          DownloadQueryCallback;
+  typedef base::Callback<void(scoped_ptr<std::vector<history::DownloadRow>>)>
+      DownloadQueryCallback;
 
   // Begins a history request to retrieve the state of all downloads in the
   // history db. 'callback' runs when the history service request is complete,
@@ -550,7 +542,7 @@ class HistoryService : public syncer::SyncableService,
   // Called on shutdown, this will tell the history backend to complete and
   // will release pointers to it. No other functions should be called once
   // cleanup has happened that may dispatch to the history thread (because it
-  // will be NULL).
+  // will be null).
   //
   // In practice, this will be called by the service manager (BrowserProcess)
   // when it is being destroyed. Because that reference is being destroyed, it
@@ -558,9 +550,6 @@ class HistoryService : public syncer::SyncableService,
   // still in memory (pending requests may be holding a reference to us).
   void Cleanup();
 
-  // Implementation of visitedlink::VisitedLinkDelegate.
-  void RebuildTable(const scoped_refptr<URLEnumerator>& enumerator) override;
-
   // Low-level Init().  Same as the public version, but adds a |no_db| parameter
   // that is only set by unittests which causes the backend to not init its DB.
   bool Init(bool no_db,
@@ -812,14 +801,14 @@ class HistoryService : public syncer::SyncableService,
   // TODO(mrossetti): Consider changing ownership. See http://crbug.com/138321
   scoped_ptr<history::InMemoryHistoryBackend> in_memory_backend_;
 
+  // The history service will inform its VisitDelegate of URLs recorded and
+  // removed from the history database. This may be null during testing.
+  scoped_ptr<history::VisitDelegate> visit_delegate_;
+
   // The history client, may be null when testing. The object should otherwise
   // outlive |HistoryService|.
   history::HistoryClient* history_client_;
 
-  // Used for propagating link highlighting data across renderers. May be null
-  // in tests.
-  scoped_ptr<visitedlink::VisitedLinkMaster> visitedlink_master_;
-
   // Has the backend finished loading? The backend is loaded once Init has
   // completed.
   bool backend_loaded_;
diff --git a/chrome/browser/history/history_service_factory.cc b/chrome/browser/history/history_service_factory.cc
index 1c39d82..6295ea9 100644
--- a/chrome/browser/history/history_service_factory.cc
+++ b/chrome/browser/history/history_service_factory.cc
@@ -10,6 +10,7 @@
 #include "chrome/browser/bookmarks/chrome_bookmark_client_factory.h"
 #include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/chrome_history_client_factory.h"
+#include "chrome/browser/history/content_visit_delegate.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
@@ -77,7 +78,8 @@ KeyedService* HistoryServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
   scoped_ptr<HistoryService> history_service(new HistoryService(
-      ChromeHistoryClientFactory::GetForProfile(profile), profile));
+      ChromeHistoryClientFactory::GetForProfile(profile),
+      scoped_ptr<history::VisitDelegate>(new ContentVisitDelegate(profile))));
   if (!history_service->Init(
           profile->GetPrefs()->GetString(prefs::kAcceptLanguages),
           history::HistoryDatabaseParamsForPath(profile->GetPath()))) {
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 7c4726a09..d007508 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
@@ -15,6 +15,7 @@
 #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/content_visit_delegate.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"
@@ -54,8 +55,9 @@ KeyedService* BuildHistoryService(content::BrowserContext* context) {
     return NULL;
   }
 
-  HistoryService* history_service = new HistoryService(
-      ChromeHistoryClientFactory::GetForProfile(profile), profile);
+  HistoryService* history_service =
+      new HistoryService(ChromeHistoryClientFactory::GetForProfile(profile),
+                         scoped_ptr<history::VisitDelegate>());
   if (history_service->Init(
           profile->GetPrefs()->GetString(prefs::kAcceptLanguages),
           history::HistoryDatabaseParamsForPath(profile->GetPath()))) {
diff --git a/chrome/browser/safe_browsing/incident_reporting/off_domain_inclusion_detector_unittest.cc b/chrome/browser/safe_browsing/incident_reporting/off_domain_inclusion_detector_unittest.cc
index cbc03fa..67b779e 100644
--- a/chrome/browser/safe_browsing/incident_reporting/off_domain_inclusion_detector_unittest.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/off_domain_inclusion_detector_unittest.cc
@@ -13,6 +13,7 @@
 #include "base/time/time.h"
 #include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/chrome_history_client_factory.h"
+#include "chrome/browser/history/content_visit_delegate.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"
@@ -67,8 +68,9 @@ KeyedService* BuildHistoryService(content::BrowserContext* context) {
     return NULL;
   }
 
-  HistoryService* history_service = new HistoryService(
-      ChromeHistoryClientFactory::GetForProfile(profile), profile);
+  HistoryService* history_service =
+      new HistoryService(ChromeHistoryClientFactory::GetForProfile(profile),
+                         scoped_ptr<history::VisitDelegate>());
   if (history_service->Init(
           profile->GetPrefs()->GetString(prefs::kAcceptLanguages),
           history::HistoryDatabaseParamsForPath(profile->GetPath()))) {
diff --git a/chrome/browser/safe_browsing/malware_details_history.h b/chrome/browser/safe_browsing/malware_details_history.h
index 7482cc5..012a748 100644
--- a/chrome/browser/safe_browsing/malware_details_history.h
+++ b/chrome/browser/safe_browsing/malware_details_history.h
@@ -26,6 +26,8 @@ namespace safe_browsing {
 typedef std::vector<GURL> RedirectChain;
 }
 
+class Profile;
+
 class MalwareDetailsRedirectsCollector
     : public base::RefCountedThreadSafe<
           MalwareDetailsRedirectsCollector,
diff --git a/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc b/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
index 2cd6cfb..f0d6578 100644
--- a/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
@@ -51,12 +51,11 @@ namespace {
 
 class HistoryMock : public HistoryService {
  public:
-  explicit HistoryMock(history::HistoryClient* client, Profile* profile)
-      : HistoryService(client, profile) {}
+  HistoryMock() : HistoryService() {}
   MOCK_METHOD0(BackendLoaded, bool(void));
 
  protected:
-  virtual ~HistoryMock() {}
+  ~HistoryMock() override {}
 };
 
 KeyedService* BuildChromeBookmarkClient(content::BrowserContext* context) {
@@ -87,7 +86,7 @@ KeyedService* BuildBookmarkModel(content::BrowserContext* context) {
 }
 
 KeyedService* BuildHistoryService(content::BrowserContext* profile) {
-  return new HistoryMock(NULL, static_cast<Profile*>(profile));
+  return new HistoryMock;
 }
 
 }  // namespace
diff --git a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
index 899b220..c02c67d 100644
--- a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
@@ -113,11 +113,10 @@ class HistoryBackendMock : public HistoryBackend {
 
 class HistoryServiceMock : public HistoryService {
  public:
-  HistoryServiceMock(history::HistoryClient* client, Profile* profile)
-      : HistoryService(client, profile), backend_(NULL) {}
+  HistoryServiceMock() : HistoryService(), backend_(nullptr) {}
 
-  virtual void ScheduleDBTask(scoped_ptr<history::HistoryDBTask> task,
-                              base::CancelableTaskTracker* tracker) override {
+  void ScheduleDBTask(scoped_ptr<history::HistoryDBTask> task,
+                      base::CancelableTaskTracker* tracker) override {
     history::HistoryDBTask* task_raw = task.get();
     task_runner_->PostTaskAndReply(
         FROM_HERE,
@@ -144,7 +143,7 @@ class HistoryServiceMock : public HistoryService {
   }
 
  private:
-  virtual ~HistoryServiceMock() {}
+  ~HistoryServiceMock() override {}
 
   void RunTaskOnDBThread(history::HistoryDBTask* task) {
     EXPECT_TRUE(task->RunOnDBThread(backend_.get(), NULL));
@@ -162,7 +161,7 @@ KeyedService* BuildFakeProfileInvalidationProvider(
 }
 
 KeyedService* BuildHistoryService(content::BrowserContext* profile) {
-  return new HistoryServiceMock(NULL, static_cast<Profile*>(profile));
+  return new HistoryServiceMock;
 }
 
 class TestTypedUrlModelAssociator : public TypedUrlModelAssociator {
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 726c9a8..7d894d4 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1521,6 +1521,8 @@
       'browser/history/chrome_history_client.h',
       'browser/history/chrome_history_client_factory.cc',
       'browser/history/chrome_history_client_factory.h',
+      'browser/history/content_visit_delegate.cc',
+      'browser/history/content_visit_delegate.h',
       'browser/history/delete_directive_handler.cc',
       'browser/history/delete_directive_handler.h',
       'browser/history/history_backend.cc',
diff --git a/chrome/test/base/testing_profile.cc b/chrome/test/base/testing_profile.cc
index e2870aa1..6e45f0b 100644
--- a/chrome/test/base/testing_profile.cc
+++ b/chrome/test/base/testing_profile.cc
@@ -23,6 +23,7 @@
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/chrome_history_client_factory.h"
+#include "chrome/browser/history/content_visit_delegate.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
@@ -214,9 +215,10 @@ KeyedService* BuildFaviconService(content::BrowserContext* profile) {
 }
 
 KeyedService* BuildHistoryService(content::BrowserContext* context) {
-  Profile* profile = static_cast<Profile*>(context);
+  Profile* profile = Profile::FromBrowserContext(context);
   HistoryService* history_service = new HistoryService(
-      ChromeHistoryClientFactory::GetForProfile(profile), profile);
+      ChromeHistoryClientFactory::GetForProfile(profile),
+      scoped_ptr<history::VisitDelegate>(new ContentVisitDelegate(profile)));
   return history_service;
 }
 
diff --git a/components/history.gypi b/components/history.gypi
index 4d6474c..384fc9c 100644
--- a/components/history.gypi
+++ b/components/history.gypi
@@ -85,6 +85,8 @@
         'history/core/browser/url_utils.h',
         'history/core/browser/visit_database.cc',
         'history/core/browser/visit_database.h',
+        'history/core/browser/visit_delegate.cc',
+        'history/core/browser/visit_delegate.h',
         'history/core/browser/visit_filter.cc',
         'history/core/browser/visit_filter.h',
         'history/core/browser/visit_tracker.cc',
diff --git a/components/history/core/browser/BUILD.gn b/components/history/core/browser/BUILD.gn
index 437eaeb..c2e1bde 100644
--- a/components/history/core/browser/BUILD.gn
+++ b/components/history/core/browser/BUILD.gn
@@ -62,6 +62,8 @@ static_library("browser") {
     "url_utils.h",
     "visit_database.cc",
     "visit_database.h",
+    "visit_delegate.cc",
+    "visit_delegate.h",
     "visit_filter.cc",
     "visit_filter.h",
     "visit_tracker.cc",
diff --git a/components/history/core/browser/url_database.h b/components/history/core/browser/url_database.h
index fb3d2f0..c6b3529 100644
--- a/components/history/core/browser/url_database.h
+++ b/components/history/core/browser/url_database.h
@@ -137,7 +137,7 @@ class URLDatabase {
    public:
     URLEnumerator();
 
-    // Retreives the next url. Returns false if no more urls are available
+    // Retrieves the next url. Returns false if no more urls are available.
     bool GetNextURL(URLRow* r);
 
    private:
@@ -153,8 +153,6 @@ class URLDatabase {
   // more than 3 times.
   bool InitURLEnumeratorForSignificant(URLEnumerator* enumerator);
 
-  // Favicons ------------------------------------------------------------------
-
   // Autocomplete --------------------------------------------------------------
 
   // Fills the given array with URLs matching the given prefix.  They will be
diff --git a/components/history/core/browser/visit_delegate.cc b/components/history/core/browser/visit_delegate.cc
new file mode 100644
index 0000000..5df16c5
--- /dev/null
+++ b/components/history/core/browser/visit_delegate.cc
@@ -0,0 +1,15 @@
+// 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/visit_delegate.h"
+
+namespace history {
+
+VisitDelegate::VisitDelegate() {
+}
+
+VisitDelegate::~VisitDelegate() {
+}
+
+}  // namespace history
diff --git a/components/history/core/browser/visit_delegate.h b/components/history/core/browser/visit_delegate.h
new file mode 100644
index 0000000..a60e7a2
--- /dev/null
+++ b/components/history/core/browser/visit_delegate.h
@@ -0,0 +1,46 @@
+// 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_VISIT_DELEGATE_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_VISIT_DELEGATE_H_
+
+#include <vector>
+
+#include "base/macros.h"
+
+class GURL;
+class HistoryService;
+
+namespace history {
+
+// VisitDelegate gets notified about URLs recorded as visited by the
+// HistoryService.
+class VisitDelegate {
+ public:
+  VisitDelegate();
+  virtual ~VisitDelegate();
+
+  // Called once HistoryService initialization is complete. Returns true if the
+  // initialization succeeded, false otherwise.
+  virtual bool Init(HistoryService* history_service) = 0;
+
+  // Called when an URL is recorded by HistoryService.
+  virtual void AddURL(const GURL& url) = 0;
+
+  // Called when a list of URLs are recorded by HistoryService.
+  virtual void AddURLs(const std::vector<GURL>& urls) = 0;
+
+  // Called when a list of URLs are removed from HistoryService.
+  virtual void DeleteURLs(const std::vector<GURL>& urls) = 0;
+
+  // Called when all URLs are removed from HistoryService.
+  virtual void DeleteAllURLs() = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(VisitDelegate);
+};
+
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_VISIT_DELEGATE_H_