Revert "Replace --top-sites flag with --no-top-sites flag. TopSites becomes the default."

Introduced new crashes.

TBR=nshkrob

Review URL: http://codereview.chromium.org/3026059

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55268 0039d316-1c4b-4281-b951-d872f2087c98

22 files changed, 157 insertions, 321 deletions

diff --git a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
index ebff335..fd6eae7 100644
--- a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
+++ b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
@@ -28,8 +28,8 @@ DOMUIThumbnailSource::~DOMUIThumbnailSource() {
 void DOMUIThumbnailSource::StartDataRequest(const std::string& path,
                                             bool is_off_the_record,
                                             int request_id) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
-    history::TopSites* top_sites = profile_->GetTopSites();
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+    scoped_refptr<history::TopSites> top_sites = profile_->GetTopSites();
     RefCountedBytes* data = NULL;
     if (top_sites->GetPageThumbnail(GURL(path), &data)) {
       // We have the thumbnail.
diff --git a/chrome/browser/dom_ui/most_visited_handler.cc b/chrome/browser/dom_ui/most_visited_handler.cc
index 3528a9c..e6e8ac14 100644
--- a/chrome/browser/dom_ui/most_visited_handler.cc
+++ b/chrome/browser/dom_ui/most_visited_handler.cc
@@ -150,7 +150,7 @@ void MostVisitedHandler::SendPagesValue() {
 }
 
 void MostVisitedHandler::StartQueryForMostVisited() {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     // Use TopSites.
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->GetMostVisitedURLs(
@@ -212,7 +212,7 @@ void MostVisitedHandler::HandleRemoveURLsFromBlacklist(const Value* urls) {
     }
     UserMetrics::RecordAction(UserMetricsAction("MostVisited_UrlRemoved"),
                               dom_ui_->GetProfile());
-    if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+    if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
       history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
       ts->RemoveBlacklistedURL(GURL(WideToASCII(url)));
       return;
@@ -227,7 +227,7 @@ void MostVisitedHandler::HandleClearBlacklist(const Value* value) {
   UserMetrics::RecordAction(UserMetricsAction("MostVisited_BlacklistCleared"),
                             dom_ui_->GetProfile());
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->ClearBlacklistedURLs();
     return;
@@ -276,7 +276,7 @@ void MostVisitedHandler::HandleAddPinnedURL(const Value* value) {
 }
 
 void MostVisitedHandler::AddPinnedURL(const MostVisitedPage& page, int index) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->AddPinnedURL(page.url, index);
     return;
@@ -315,7 +315,7 @@ void MostVisitedHandler::HandleRemovePinnedURL(const Value* value) {
 }
 
 void MostVisitedHandler::RemovePinnedURL(const GURL& url) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->RemovePinnedURL(url);
     return;
@@ -485,7 +485,7 @@ void MostVisitedHandler::SetPagesValue(std::vector<PageUsageData*>* data) {
 
 void MostVisitedHandler::SetPagesValueFromTopSites(
     const history::MostVisitedURLList& data) {
-  DCHECK(!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites));
+  DCHECK(CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites));
   pages_value_.reset(new ListValue);
   for (size_t i = 0; i < data.size(); i++) {
     const history::MostVisitedURL& url = data[i];
@@ -607,7 +607,7 @@ void MostVisitedHandler::Observe(NotificationType type,
 }
 
 void MostVisitedHandler::BlacklistURL(const GURL& url) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->AddBlacklistedURL(url);
     return;
diff --git a/chrome/browser/history/expire_history_backend_unittest.cc b/chrome/browser/history/expire_history_backend_unittest.cc
index 95b391f..ca822bc 100644
--- a/chrome/browser/history/expire_history_backend_unittest.cc
+++ b/chrome/browser/history/expire_history_backend_unittest.cc
@@ -16,10 +16,8 @@
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/text_database_manager.h"
 #include "chrome/browser/history/thumbnail_database.h"
-#include "chrome/browser/history/top_sites.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/thumbnail_score.h"
-#include "chrome/test/testing_profile.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
 #include "gfx/codec/jpeg_codec.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -92,8 +90,6 @@ class ExpireHistoryTest : public testing::Test,
   scoped_ptr<ArchivedDatabase> archived_db_;
   scoped_ptr<ThumbnailDatabase> thumb_db_;
   scoped_ptr<TextDatabaseManager> text_db_;
-  TestingProfile profile_;
-  scoped_refptr<TopSites> top_sites_;
 
   // Time at the beginning of the test, so everybody agrees what "now" is.
   const Time now_;
@@ -138,7 +134,6 @@ class ExpireHistoryTest : public testing::Test,
 
     expirer_.SetDatabases(main_db_.get(), archived_db_.get(), thumb_db_.get(),
                           text_db_.get());
-    top_sites_ = profile_.GetTopSites();
   }
 
   void TearDown() {
@@ -150,7 +145,6 @@ class ExpireHistoryTest : public testing::Test,
     archived_db_.reset();
     thumb_db_.reset();
     text_db_.reset();
-    TopSites::DeleteTopSites(top_sites_);
     file_util::Delete(dir_, true);
   }
 
@@ -217,9 +211,9 @@ void ExpireHistoryTest::AddExampleData(URLID url_ids[3], Time visit_times[4]) {
 
   Time time;
   GURL gurl;
-  top_sites_->SetPageThumbnail(url_row1.url(), *thumbnail, score);
-  top_sites_->SetPageThumbnail(url_row2.url(), *thumbnail, score);
-  top_sites_->SetPageThumbnail(url_row3.url(), *thumbnail, score);
+  thumb_db_->SetPageThumbnail(gurl, url_ids[0], *thumbnail, score, time);
+  thumb_db_->SetPageThumbnail(gurl, url_ids[1], *thumbnail, score, time);
+  thumb_db_->SetPageThumbnail(gurl, url_ids[2], *thumbnail, score, time);
 
   // Four visits.
   VisitRow visit_row1;
@@ -277,12 +271,8 @@ bool ExpireHistoryTest::HasFavIcon(FavIconID favicon_id) {
 }
 
 bool ExpireHistoryTest::HasThumbnail(URLID url_id) {
-  URLRow info;
-  if (!main_db_->GetURLRow(url_id, &info))
-    return false;
-  GURL url = info.url();
-  RefCountedBytes *data;
-  return top_sites_->GetPageThumbnail(url, &data);
+  std::vector<unsigned char> temp_data;
+  return thumb_db_->GetPageThumbnail(url_id, &temp_data);
 }
 
 int ExpireHistoryTest::CountTextMatchesForURL(const GURL& url) {
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 1c58f74..8e1c5fb 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -581,7 +581,7 @@ void HistoryBackend::InitImpl() {
 
   // Thumbnail database.
   thumbnail_db_.reset(new ThumbnailDatabase());
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     if (!db_->needs_version_18_migration()) {
       // No convertion needed - use new filename right away.
       thumbnail_name = GetFaviconsFileName();
@@ -598,7 +598,7 @@ void HistoryBackend::InitImpl() {
     thumbnail_db_.reset();
   }
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     if (db_->needs_version_18_migration()) {
       LOG(INFO) << "Starting TopSites migration";
       delegate_->StartTopSitesMigration();
diff --git a/chrome/browser/history/history_backend_unittest.cc b/chrome/browser/history/history_backend_unittest.cc
index 780038d..24cc1cd 100644
--- a/chrome/browser/history/history_backend_unittest.cc
+++ b/chrome/browser/history/history_backend_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "base/file_path.h"
 #include "base/file_util.h"
-#include "base/command_line.h"
 #include "base/path_service.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
@@ -14,7 +13,6 @@
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
 #include "chrome/browser/history/in_memory_database.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
@@ -404,9 +402,6 @@ TEST_F(HistoryBackendTest, URLsNoLongerBookmarked) {
 
 TEST_F(HistoryBackendTest, GetPageThumbnailAfterRedirects) {
   ASSERT_TRUE(backend_.get());
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;
-
 
   const char* base_url = "http://mail";
   const char* thumbnail_url = "http://mail.google.com";
@@ -603,9 +598,6 @@ TEST_F(HistoryBackendTest, StripUsernamePasswordTest) {
 }
 
 TEST_F(HistoryBackendTest, DeleteThumbnailsDatabaseTest) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;
-
   EXPECT_TRUE(backend_->thumbnail_db_->NeedsMigrationToTopSites());
   backend_->delegate_->StartTopSitesMigration();
   EXPECT_FALSE(backend_->thumbnail_db_->NeedsMigrationToTopSites());
diff --git a/chrome/browser/history/history_database.cc b/chrome/browser/history/history_database.cc
index 7869fcc..26bb81a 100644
--- a/chrome/browser/history/history_database.cc
+++ b/chrome/browser/history/history_database.cc
@@ -134,11 +134,14 @@ void HistoryDatabase::BeginExclusiveMode() {
 
 // static
 int HistoryDatabase::GetCurrentVersion() {
-  // If we don't use TopSites, we are one version number behind.
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return 17;  // Last pre-TopSites version.
-  else
+  // Temporary solution while TopSites is behind a flag. If there is
+  // no flag, we are still using the Thumbnails file, i.e. we are at
+  // version 17.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     return kCurrentVersionNumber;
+  } else {
+    return kCurrentVersionNumber - 1;
+  }
 }
 
 void HistoryDatabase::BeginTransaction() {
@@ -283,7 +286,7 @@ sql::InitStatus HistoryDatabase::EnsureCurrentVersion(
   if (cur_version == 17)
     needs_version_18_migration_ = true;
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites) &&
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites) &&
       cur_version == 18) {
     // Set DB version back to pre-top sites.
     cur_version = 17;
diff --git a/chrome/browser/history/history_types.h b/chrome/browser/history/history_types.h
index 21e8067..0c283b1 100644
--- a/chrome/browser/history/history_types.h
+++ b/chrome/browser/history/history_types.h
@@ -13,14 +13,12 @@
 #include <vector>
 
 #include "base/basictypes.h"
-#include "base/ref_counted_memory.h"
 #include "base/stack_container.h"
 #include "base/string16.h"
 #include "base/time.h"
 #include "chrome/browser/history/snippet.h"
 #include "chrome/common/page_transition_types.h"
 #include "chrome/common/ref_counted_util.h"
-#include "chrome/common/thumbnail_score.h"
 #include "googleurl/src/gurl.h"
 
 namespace history {
@@ -529,15 +527,6 @@ struct MostVisitedURL {
   }
 };
 
-// Used by TopSites to store the thumbnails.
-struct Images {
-  scoped_refptr<RefCountedBytes> thumbnail;
-  ThumbnailScore thumbnail_score;
-
-  // TODO(brettw): this will eventually store the favicon.
-  // scoped_refptr<RefCountedBytes> favicon;
-};
-
 typedef std::vector<MostVisitedURL> MostVisitedURLList;
 
 // Used for intermediate history result operations.
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index 063414f..c8db05a 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -24,7 +24,6 @@
 #include "app/sql/statement.h"
 #include "base/basictypes.h"
 #include "base/callback.h"
-#include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
@@ -42,7 +41,6 @@
 #include "chrome/browser/history/in_memory_history_backend.h"
 #include "chrome/browser/history/page_usage_data.h"
 #include "chrome/common/chrome_paths.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
@@ -687,9 +685,6 @@ TEST_F(HistoryTest, Segments) {
 // This just tests history system -> thumbnail database integration, the actual
 // thumbnail tests are in its own file.
 TEST_F(HistoryTest, Thumbnails) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   scoped_refptr<HistoryService> history(new HistoryService);
   history_service_ = history;
   ASSERT_TRUE(history->Init(history_dir_, NULL));
diff --git a/chrome/browser/history/thumbnail_database.cc b/chrome/browser/history/thumbnail_database.cc
index 979accf..8bf203d 100644
--- a/chrome/browser/history/thumbnail_database.cc
+++ b/chrome/browser/history/thumbnail_database.cc
@@ -130,7 +130,7 @@ sql::InitStatus ThumbnailDatabase::OpenDatabase(sql::Connection* db,
 
 bool ThumbnailDatabase::InitThumbnailTable() {
   if (!db_.DoesTableExist("thumbnails")) {
-    if (!CommandLine::ForCurrentProcess()-> HasSwitch(switches::kNoTopSites)) {
+    if (CommandLine::ForCurrentProcess()-> HasSwitch(switches::kTopSites)) {
       use_top_sites_ = true;
       return true;
     }
@@ -231,10 +231,8 @@ void ThumbnailDatabase::SetPageThumbnail(
     const SkBitmap& thumbnail,
     const ThumbnailScore& score,
     base::Time time) {
-  if (use_top_sites_) {
-    LOG(WARNING) << "Use TopSites instead.";
+  if (use_top_sites_)
     return;  // Not possible after migration to TopSites.
-  }
 
   if (!thumbnail.isNull()) {
     bool add_thumbnail = true;
@@ -288,10 +286,8 @@ void ThumbnailDatabase::SetPageThumbnail(
 
 bool ThumbnailDatabase::GetPageThumbnail(URLID id,
                                          std::vector<unsigned char>* data) {
-  if (use_top_sites_) {
-    LOG(WARNING) << "Use TopSites instead.";
+  if (use_top_sites_)
     return false;  // Not possible after migration to TopSites.
-  }
 
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "SELECT data FROM thumbnails WHERE url_id=?"));
@@ -307,10 +303,8 @@ bool ThumbnailDatabase::GetPageThumbnail(URLID id,
 }
 
 bool ThumbnailDatabase::DeleteThumbnail(URLID id) {
-  if (use_top_sites_) {
-    LOG(WARNING) << "Use TopSites instead.";
+  if (use_top_sites_)
     return true;  // Not possible after migration to TopSites.
-  }
 
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "DELETE FROM thumbnails WHERE url_id = ?"));
@@ -323,10 +317,8 @@ bool ThumbnailDatabase::DeleteThumbnail(URLID id) {
 
 bool ThumbnailDatabase::ThumbnailScoreForId(URLID id,
                                             ThumbnailScore* score) {
-  if (use_top_sites_) {
-    LOG(WARNING) << "Use TopSites instead.";
+  if (use_top_sites_)
     return false;  // Not possible after migration to TopSites.
-  }
 
   // Fetch the current thumbnail's information to make sure we
   // aren't replacing a good thumbnail with one that's worse.
diff --git a/chrome/browser/history/thumbnail_database_unittest.cc b/chrome/browser/history/thumbnail_database_unittest.cc
index 24c990b..4d2c2bf 100644
--- a/chrome/browser/history/thumbnail_database_unittest.cc
+++ b/chrome/browser/history/thumbnail_database_unittest.cc
@@ -6,7 +6,6 @@
 #include <vector>
 
 #include "base/basictypes.h"
-#include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
@@ -14,7 +13,6 @@
 #include "base/scoped_temp_dir.h"
 #include "chrome/browser/history/thumbnail_database.h"
 #include "chrome/common/chrome_paths.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
 #include "gfx/codec/jpeg_codec.h"
@@ -72,9 +70,6 @@ class ThumbnailDatabaseTest : public testing::Test {
 };
 
 TEST_F(ThumbnailDatabaseTest, AddDelete) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   ASSERT_EQ(sql::INIT_OK, db.Init(file_name_, NULL));
 
@@ -117,9 +112,6 @@ TEST_F(ThumbnailDatabaseTest, AddDelete) {
 }
 
 TEST_F(ThumbnailDatabaseTest, UseLessBoringThumbnails) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   Time now = Time::Now();
   ASSERT_EQ(sql::INIT_OK, db.Init(file_name_, NULL));
@@ -154,9 +146,6 @@ TEST_F(ThumbnailDatabaseTest, UseLessBoringThumbnails) {
 }
 
 TEST_F(ThumbnailDatabaseTest, UseAtTopThumbnails) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   Time now = Time::Now();
   ASSERT_EQ(sql::INIT_OK, db.Init(file_name_, NULL));
@@ -228,9 +217,6 @@ TEST_F(ThumbnailDatabaseTest, UseAtTopThumbnails) {
 }
 
 TEST_F(ThumbnailDatabaseTest, ThumbnailTimeDegradation) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   const Time kNow = Time::Now();
   const Time kThreeHoursAgo = kNow - TimeDelta::FromHours(4);
@@ -275,9 +261,6 @@ TEST_F(ThumbnailDatabaseTest, NeverAcceptTotallyBoringThumbnail) {
   // should replace a thumbnail with another because of reasons other
   // than straight up boringness score, still reject because the
   // thumbnail is totally boring.
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   Time now = Time::Now();
   ASSERT_EQ(sql::INIT_OK, db.Init(file_name_, NULL));
@@ -349,9 +332,6 @@ TEST_F(ThumbnailDatabaseTest, NeverAcceptTotallyBoringThumbnail) {
 }
 
 TEST_F(ThumbnailDatabaseTest, NeedsMigrationToTopSites) {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites))
-    return;  // TopSitesTest replaces this.
-
   ThumbnailDatabase db;
   ASSERT_EQ(sql::INIT_OK, db.Init(file_name_, NULL));
   db.BeginTransaction();
diff --git a/chrome/browser/history/top_sites.cc b/chrome/browser/history/top_sites.cc
index eb0fb74..7d8c66a 100644
--- a/chrome/browser/history/top_sites.cc
+++ b/chrome/browser/history/top_sites.cc
@@ -54,15 +54,10 @@ TopSites::TopSites(Profile* profile) : profile_(profile),
                                        waiting_for_results_(true),
                                        blacklist_(NULL),
                                        pinned_urls_(NULL) {
-  if (!profile_)
-    return;
-
-  if (NotificationService::current()) {
-    registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
-                   Source<Profile>(profile_));
-    registrar_.Add(this, NotificationType::NAV_ENTRY_COMMITTED,
-                   NotificationService::AllSources());
-  }
+  registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
+                 Source<Profile>(profile_));
+  registrar_.Add(this, NotificationType::NAV_ENTRY_COMMITTED,
+                 NotificationService::AllSources());
 
   blacklist_ = profile_->GetPrefs()->
       GetMutableDictionary(prefs::kNTPMostVisitedURLsBlacklist);
@@ -95,14 +90,16 @@ void TopSites::ReadDatabase() {
   std::map<GURL, Images> thumbnails;
 
   DCHECK(db_.get());
-  MostVisitedURLList top_urls;
-  db_->GetPageThumbnails(&top_urls, &thumbnails);
-  MostVisitedURLList copy(top_urls);  // StoreMostVisited destroys the list.
-  StoreMostVisited(&top_urls);
-  if (AddPrepopulatedPages(&copy))
-    UpdateMostVisited(copy);
+  {
+    AutoLock lock(lock_);
+    MostVisitedURLList top_urls;
+    db_->GetPageThumbnails(&top_urls, &thumbnails);
+    MostVisitedURLList copy(top_urls);  // StoreMostVisited destroys the list.
+    StoreMostVisited(&top_urls);
+    if (AddPrepopulatedPages(&copy))
+      UpdateMostVisited(copy);
+  }  // Lock is released here.
 
-  AutoLock lock(lock_);
   for (size_t i = 0; i < top_sites_.size(); i++) {
     GURL url = top_sites_[i].url;
     Images thumbnail = thumbnails[url];
@@ -148,14 +145,12 @@ bool TopSites::SetPageThumbnail(const GURL& url,
     return true;
   }
 
-  AutoLock lock(lock_);
-  return SetPageThumbnailEncoded(url, thumbnail_data, score);
+  return SetPageThumbnail(url, thumbnail_data, score);
 }
 
-bool TopSites::SetPageThumbnailEncoded(const GURL& url,
-                                       const RefCountedBytes* thumbnail,
-                                       const ThumbnailScore& score) {
-  lock_.AssertAcquired();
+bool TopSites::SetPageThumbnail(const GURL& url,
+                                const RefCountedBytes* thumbnail,
+                                const ThumbnailScore& score) {
   if (!SetPageThumbnailNoDB(url, thumbnail, score))
     return false;
 
@@ -176,7 +171,7 @@ bool TopSites::SetPageThumbnailEncoded(const GURL& url,
 
 void TopSites::WriteThumbnailToDB(const MostVisitedURL& url,
                                   int url_rank,
-                                  const Images& thumbnail) {
+                                  const TopSites::Images& thumbnail) {
   DCHECK(db_.get());
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::DB));
   db_->SetPageThumbnail(url, url_rank, thumbnail);
@@ -186,7 +181,7 @@ void TopSites::WriteThumbnailToDB(const MostVisitedURL& url,
 bool TopSites::SetPageThumbnailNoDB(const GURL& url,
                                     const RefCountedBytes* thumbnail_data,
                                     const ThumbnailScore& score) {
-  lock_.AssertAcquired();
+  AutoLock lock(lock_);
 
   std::map<GURL, size_t>::iterator found = canonical_urls_.find(url);
   if (found == canonical_urls_.end()) {
@@ -242,21 +237,15 @@ void TopSites::GetMostVisitedURLs(CancelableRequestConsumer* consumer,
     return;
 
   MostVisitedURLList filtered_urls;
-  {
-    AutoLock lock(lock_);
-    ApplyBlacklistAndPinnedURLs(top_sites_, &filtered_urls);
-  }
+  ApplyBlacklistAndPinnedURLs(top_sites_, &filtered_urls);
+
   request->ForwardResult(GetTopSitesCallback::TupleType(filtered_urls));
 }
 
 bool TopSites::GetPageThumbnail(const GURL& url, RefCountedBytes** data) const {
-  AutoLock lock(lock_);
   std::map<GURL, Images>::const_iterator found = top_images_.find(url);
-  if (found == top_images_.end()) {
-    found = temp_thumbnails_map_.find(url);
-    if (found == temp_thumbnails_map_.end())
-      return false;  // No thumbnail for this URL.
-  }
+  if (found == top_images_.end())
+    return false;  // No thumbnail for this URL.
 
   Images image = found->second;
   *data = image.thumbnail.get();
@@ -273,11 +262,8 @@ static int IndexOf(const MostVisitedURLList& urls, const GURL& url) {
 
 int TopSites::GetIndexForChromeStore(const MostVisitedURLList& urls) {
   GURL store_url = MostVisitedHandler::GetChromeStoreURLWithLocale();
-  {
-    AutoLock lock(lock_);
-    if (IsBlacklisted(store_url))
-      return -1;
-  }
+  if (IsBlacklisted(store_url))
+    return -1;
 
   if (IndexOf(urls, store_url) != -1)
     return -1;  // It's already there, no need to add.
@@ -304,9 +290,6 @@ bool TopSites::AddChromeStore(MostVisitedURLList* urls) {
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableApps))
     return false;
 
-  if (!profile_)
-    return false;
-
   ExtensionsService* service = profile_->GetExtensionsService();
   if (!service || service->HasApps())
     return false;
@@ -388,7 +371,6 @@ void TopSites::MigratePinnedURLs() {
 void TopSites::ApplyBlacklistAndPinnedURLs(const MostVisitedURLList& urls,
                                            MostVisitedURLList* out) {
   MostVisitedURLList urls_copy;
-  lock_.AssertAcquired();
   for (size_t i = 0; i < urls.size(); i++) {
     if (!IsBlacklisted(urls[i].url))
       urls_copy.push_back(urls[i]);
@@ -435,12 +417,10 @@ void TopSites::ApplyBlacklistAndPinnedURLs(const MostVisitedURLList& urls,
 }
 
 std::wstring TopSites::GetURLString(const GURL& url) {
-  lock_.AssertAcquired();
   return ASCIIToWide(GetCanonicalURL(url).spec());
 }
 
 std::wstring TopSites::GetURLHash(const GURL& url) {
-  lock_.AssertAcquired();
   return ASCIIToWide(MD5String(GetCanonicalURL(url).spec()));
 }
 
@@ -450,33 +430,27 @@ void TopSites::UpdateMostVisited(MostVisitedURLList most_visited) {
   std::vector<size_t> added;    // Indices into most_visited.
   std::vector<size_t> deleted;  // Indices into top_sites_.
   std::vector<size_t> moved;    // Indices into most_visited.
-
   DiffMostVisited(top_sites_, most_visited, &added, &deleted, &moved);
 
   // #added == #deleted; #added + #moved = total.
   last_num_urls_changed_ = added.size() + moved.size();
 
-  {
-    AutoLock lock(lock_);
+  // Process the diff: delete from images and disk, add to disk.
+  // Delete all the thumbnails associated with URLs that were deleted.
+  for (size_t i = 0; i < deleted.size(); i++) {
+    const MostVisitedURL& deleted_url = top_sites_[deleted[i]];
+    std::map<GURL, Images>::iterator found =
+        top_images_.find(deleted_url.url);
+    if (found != top_images_.end())
+      top_images_.erase(found);
 
-    // Process the diff: delete from images and disk, add to disk.
-    // Delete all the thumbnails associated with URLs that were deleted.
-    for (size_t i = 0; i < deleted.size(); i++) {
-      const MostVisitedURL& deleted_url = top_sites_[deleted[i]];
-      std::map<GURL, Images>::iterator found =
-          top_images_.find(deleted_url.url);
-      if (found != top_images_.end())
-        top_images_.erase(found);
-    }
+    // Delete from disk.
+    if (db_.get())
+      db_->RemoveURL(deleted_url);
   }
 
-  // Write the updates to the DB.
   if (db_.get()) {
-    for (size_t i = 0; i < deleted.size(); i++) {
-      const MostVisitedURL& deleted_url = top_sites_[deleted[i]];
-      if (db_.get())
-        db_->RemoveURL(deleted_url);
-    }
+    // Write both added and moved urls.
     for (size_t i = 0; i < added.size(); i++) {
       const MostVisitedURL& added_url = most_visited[added[i]];
       db_->SetPageThumbnail(added_url, added[i], Images());
@@ -510,9 +484,6 @@ void TopSites::UpdateMostVisited(MostVisitedURLList most_visited) {
 
 void TopSites::OnMigrationDone() {
   migration_in_progress_ = false;
-  if (!profile_)
-    return;
-
   HistoryService* hs = profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   // |hs| may be null during unit tests.
   if (!hs)
@@ -550,9 +521,6 @@ void TopSites::StartQueryForThumbnail(size_t index) {
     return;
   }
 
-  if (!profile_)
-    return;
-
   HistoryService* hs = profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   // |hs| may be null during unit tests.
   if (!hs)
@@ -565,7 +533,6 @@ void TopSites::StartQueryForThumbnail(size_t index) {
 }
 
 void TopSites::GenerateCanonicalURLs() {
-  lock_.AssertAcquired();
   canonical_urls_.clear();
   for (size_t i = 0; i < top_sites_.size(); i++) {
     const MostVisitedURL& mv = top_sites_[i];
@@ -575,9 +542,8 @@ void TopSites::GenerateCanonicalURLs() {
 
 void TopSites::StoreMostVisited(MostVisitedURLList* most_visited) {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::DB));
-  AutoLock lock(lock_);
-  top_sites_.clear();
   // Take ownership of the most visited data.
+  top_sites_.clear();
   top_sites_.swap(*most_visited);
   waiting_for_results_ = false;
 
@@ -594,8 +560,8 @@ void TopSites::StoreMostVisited(MostVisitedURLList* most_visited) {
       // when we add a temp thumbnail, redirect chain is not known.
       // This is slow, but temp_thumbnails_map_ should have very few URLs.
       if (canonical_url == GetCanonicalURL(it->first)) {
-        SetPageThumbnailEncoded(mv.url, it->second.thumbnail,
-                                it->second.thumbnail_score);
+        SetPageThumbnail(mv.url, it->second.thumbnail,
+                         it->second.thumbnail_score);
         temp_thumbnails_map_.erase(it);
         break;
       }
@@ -618,7 +584,6 @@ void TopSites::StoreRedirectChain(const RedirectList& redirects,
 }
 
 GURL TopSites::GetCanonicalURL(const GURL& url) const {
-  lock_.AssertAcquired();
   std::map<GURL, size_t>::const_iterator found = canonical_urls_.find(url);
   if (found == canonical_urls_.end())
     return url;  // Unknown URL - return unchanged.
@@ -687,9 +652,6 @@ void TopSites::StartQueryForMostVisited() {
         &cancelable_consumer_,
         NewCallback(this, &TopSites::OnTopSitesAvailable));
   } else {
-    if (!profile_)
-      return;
-
     HistoryService* hs = profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
     // |hs| may be null during unit tests.
     if (hs) {
@@ -711,20 +673,17 @@ void TopSites::StartMigration() {
 }
 
 void TopSites::AddBlacklistedURL(const GURL& url) {
-  AutoLock lock(lock_);
-  RemovePinnedURLLocked(url);
+  RemovePinnedURL(url);
   Value* dummy = Value::CreateNullValue();
   blacklist_->SetWithoutPathExpansion(GetURLHash(url), dummy);
 }
 
 bool TopSites::IsBlacklisted(const GURL& url) {
-  lock_.AssertAcquired();
   bool result = blacklist_->HasKey(GetURLHash(url));
   return result;
 }
 
 void TopSites::RemoveBlacklistedURL(const GURL& url) {
-  AutoLock lock(lock_);
   blacklist_->RemoveWithoutPathExpansion(GetURLHash(url), NULL);
 }
 
@@ -743,22 +702,22 @@ void TopSites::AddPinnedURL(const GURL& url, size_t pinned_index) {
   }
 
   Value* index = Value::CreateIntegerValue(pinned_index);
-  AutoLock lock(lock_);
   pinned_urls_->SetWithoutPathExpansion(GetURLString(url), index);
 }
 
 void TopSites::RemovePinnedURL(const GURL& url) {
-  AutoLock lock(lock_);
-  RemovePinnedURLLocked(url);
+  pinned_urls_->RemoveWithoutPathExpansion(GetURLString(url), NULL);
 }
 
-void TopSites::RemovePinnedURLLocked(const GURL& url) {
-  lock_.AssertAcquired();
-  pinned_urls_->RemoveWithoutPathExpansion(GetURLString(url), NULL);
+bool TopSites::GetIndexOfPinnedURL(const GURL& url, size_t* index) {
+  int tmp;
+  bool result = pinned_urls_->GetIntegerWithoutPathExpansion(
+      GetURLString(url), &tmp);
+  *index = static_cast<size_t>(tmp);
+  return result;
 }
 
 bool TopSites::IsURLPinned(const GURL& url) {
-  AutoLock lock(lock_);
   int tmp;
   bool result = pinned_urls_->GetIntegerWithoutPathExpansion(
       GetURLString(url), &tmp);
@@ -779,24 +738,6 @@ bool TopSites::GetPinnedURLAtIndex(size_t index, GURL* url) {
   return false;
 }
 
-// static
-void TopSites::DeleteTopSites(scoped_refptr<TopSites>& ptr) {
-  if (!ptr.get() || !MessageLoop::current())
-    return;
-  if (ChromeThread::IsWellKnownThread(ChromeThread::UI)) {
-    ptr = NULL;
-  } else {
-    // Need to roll our own UI thread.
-    ChromeThread ui_loop(ChromeThread::UI, MessageLoop::current());
-    ptr = NULL;
-    MessageLoop::current()->RunAllPending();
-  }
-}
-
-void TopSites::ClearProfile() {
-  profile_ = NULL;
-}
-
 base::TimeDelta TopSites::GetUpdateDelay() {
   if (top_sites_.size() == 0)
     return base::TimeDelta::FromSeconds(30);
@@ -817,10 +758,7 @@ void TopSites::OnTopSitesAvailable(
 
   if (!pending_callbacks_.empty()) {
     MostVisitedURLList filtered_urls;
-    {
-      AutoLock lock(lock_);
-      ApplyBlacklistAndPinnedURLs(pages, &filtered_urls);
-    }
+    ApplyBlacklistAndPinnedURLs(pages, &filtered_urls);
 
     PendingCallbackSet::iterator i;
     for (i = pending_callbacks_.begin();
@@ -839,9 +777,6 @@ void TopSites::OnThumbnailAvailable(CancelableRequestProvider::Handle handle,
   if (mock_history_service_) {
     index = handle;
   } else {
-    if (!profile_)
-      return;
-
     HistoryService* hs = profile_ ->GetHistoryService(Profile::EXPLICIT_ACCESS);
     index = cancelable_consumer_.GetClientData(hs, handle);
   }
@@ -852,8 +787,7 @@ void TopSites::OnThumbnailAvailable(CancelableRequestProvider::Handle handle,
 
   if (thumbnail.get() && thumbnail->size()) {
     const MostVisitedURL& url = top_sites_[index];
-    AutoLock lock(lock_);
-    SetPageThumbnailEncoded(url.url, thumbnail, ThumbnailScore());
+    SetPageThumbnail(url.url, thumbnail, ThumbnailScore());
   }
 
   if (migration_in_progress_ && migration_pending_urls_.empty() &&
@@ -869,7 +803,6 @@ void TopSites::Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details) {
   if (type == NotificationType::HISTORY_URLS_DELETED) {
-    AutoLock lock(lock_);
     Details<history::URLsDeletedDetails> deleted_details(details);
     if (deleted_details->all_history) {
       top_sites_.clear();
@@ -888,7 +821,7 @@ void TopSites::Observe(NotificationType type,
       for (std::set<size_t>::reverse_iterator i = indices_to_delete.rbegin();
            i != indices_to_delete.rend(); i++) {
         size_t index = *i;
-        RemovePinnedURLLocked(top_sites_[index].url);
+        RemovePinnedURL(top_sites_[index].url);
         top_sites_.erase(top_sites_.begin() + index);
       }
     }
@@ -897,14 +830,11 @@ void TopSites::Observe(NotificationType type,
     StartQueryForMostVisited();
   } else if (type == NotificationType::NAV_ENTRY_COMMITTED) {
     if (top_sites_.size() < kTopSitesNumber) {
-      NavigationController::LoadCommittedDetails* load_details =
-          Details<NavigationController::LoadCommittedDetails>(details).ptr();
-      if (!load_details)
-        return;
-      GURL url = load_details->entry->url();
+      const NavigationController::LoadCommittedDetails& load_details =
+          *Details<NavigationController::LoadCommittedDetails>(details).ptr();
+      GURL url = load_details.entry->url();
       if (canonical_urls_.find(url) == canonical_urls_.end() &&
-          HistoryService::CanAddURL(url)) {
-        AutoLock lock(lock_);
+           HistoryService::CanAddURL(url)) {
         // Add this page to the known pages in case the thumbnail comes
         // in before we get the results.
         MostVisitedURL mv;
diff --git a/chrome/browser/history/top_sites.h b/chrome/browser/history/top_sites.h
index b460afb..09d0af0 100644
--- a/chrome/browser/history/top_sites.h
+++ b/chrome/browser/history/top_sites.h
@@ -18,7 +18,6 @@
 #include "base/ref_counted.h"
 #include "base/ref_counted_memory.h"
 #include "chrome/browser/cancelable_request.h"
-#include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/page_usage_data.h"
@@ -48,11 +47,9 @@ typedef std::vector<MostVisitedURL> MostVisitedURLList;
 // new tab page requests on the I/O thread without proxying to the UI thread is
 // a nontrivial performance win, especially when the browser is starting and
 // the UI thread is busy.
-class TopSites :
-      public base::RefCountedThreadSafe<TopSites,
-                                        ChromeThread::DeleteOnUIThread>,
-      public NotificationObserver,
-      public CancelableRequestProvider {
+class TopSites : public NotificationObserver,
+                 public base::RefCountedThreadSafe<TopSites>,
+                 public CancelableRequestProvider {
  public:
   explicit TopSites(Profile* profile);
 
@@ -71,6 +68,14 @@ class TopSites :
         size_t index) = 0;
   };
 
+  struct Images {
+    scoped_refptr<RefCountedBytes> thumbnail;
+    ThumbnailScore thumbnail_score;
+
+    // TODO(brettw): this will eventually store the favicon.
+    // scoped_refptr<RefCountedBytes> favicon;
+  };
+
   // Initializes TopSites.
   void Init(const FilePath& db_name);
 
@@ -103,6 +108,9 @@ class TopSites :
   // Add a  URL to the blacklist.
   void AddBlacklistedURL(const GURL& url);
 
+  // Returns true if the URL is blacklisted.
+  bool IsBlacklisted(const GURL& url);
+
   // Removes a URL from the blacklist.
   void RemoveBlacklistedURL(const GURL& url);
 
@@ -114,6 +122,9 @@ class TopSites :
   // Pin a URL at |index|.
   void AddPinnedURL(const GURL& url, size_t index);
 
+  // Get the index of a URL. Returns true if |url| is pinned.
+  bool GetIndexOfPinnedURL(const GURL& url, size_t* index);
+
   // Returns true if a URL is pinned.
   bool IsURLPinned(const GURL& url);
 
@@ -124,18 +135,8 @@ class TopSites :
   // is a URL pinned at |index|.
   bool GetPinnedURLAtIndex(size_t index, GURL* out);
 
-  // TopSites must be deleted on a UI thread. This happens
-  // automatically in a real browser, but in unit_tests we don't have
-  // a real UI thread. Use this function to delete a TopSites object.
-  static void DeleteTopSites(scoped_refptr<TopSites>& ptr);
-
-  // Sets the profile pointer to NULL. This is for the case where
-  // TopSites outlives the profile, since TopSites is refcounted.
-  void ClearProfile();
-
  private:
-  friend struct ChromeThread::DeleteOnThread<ChromeThread::UI>;
-  friend class DeleteTask<TopSites>;
+  friend class base::RefCountedThreadSafe<TopSites>;
   friend class TopSitesTest;
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, GetMostVisited);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, RealDatabase);
@@ -164,9 +165,9 @@ class TopSites :
 
   // A version of SetPageThumbnail that takes RefCountedBytes as
   // returned by HistoryService.
-  bool SetPageThumbnailEncoded(const GURL& url,
-                               const RefCountedBytes* thumbnail,
-                               const ThumbnailScore& score);
+  bool SetPageThumbnail(const GURL& url,
+                        const RefCountedBytes* thumbnail,
+                        const ThumbnailScore& score);
 
   // Query history service for the list of available thumbnails.
   void StartQueryForMostVisited();
@@ -228,12 +229,6 @@ class TopSites :
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
-  // Returns true if the URL is blacklisted.
-  bool IsBlacklisted(const GURL& url);
-
-  // A variant of RemovePinnedURL that must be called within a lock.
-  void RemovePinnedURLLocked(const GURL& url);
-
   // Returns the delay until the next update of history is needed.
   // Uses num_urls_changed
   base::TimeDelta GetUpdateDelay();
@@ -248,7 +243,7 @@ class TopSites :
   // Write a thumbnail to database.
   void WriteThumbnailToDB(const MostVisitedURL& url,
                           int url_rank,
-                          const Images& thumbnail);
+                          const TopSites::Images& thumbnail);
 
   // Updates the top sites list and writes the difference to disk.
   void UpdateMostVisited(MostVisitedURLList most_visited);
diff --git a/chrome/browser/history/top_sites_database.cc b/chrome/browser/history/top_sites_database.cc
index 96da3f9..99f0bb4 100644
--- a/chrome/browser/history/top_sites_database.cc
+++ b/chrome/browser/history/top_sites_database.cc
@@ -5,7 +5,6 @@
 #include "app/sql/transaction.h"
 #include "base/string_util.h"
 #include "chrome/browser/diagnostics/sqlite_diagnostics.h"
-#include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/history/top_sites_database.h"
 
@@ -49,7 +48,7 @@ bool TopSitesDatabaseImpl::InitThumbnailTable() {
 
 void TopSitesDatabaseImpl::GetPageThumbnails(MostVisitedURLList* urls,
                                              std::map<GURL,
-                                             Images>* thumbnails) {
+                                             TopSites::Images>* thumbnails) {
   sql::Statement statement(db_.GetCachedStatement(
       SQL_FROM_HERE,
       "SELECT url, url_rank, title, thumbnail, redirects, "
@@ -76,7 +75,7 @@ void TopSitesDatabaseImpl::GetPageThumbnails(MostVisitedURLList* urls,
 
     std::vector<unsigned char> data;
     statement.ColumnBlobAsVector(3, &data);
-    Images thumbnail;
+    TopSites::Images thumbnail;
     thumbnail.thumbnail = RefCountedBytes::TakeVector(&data);
     thumbnail.thumbnail_score.boring_score = statement.ColumnDouble(5);
     thumbnail.thumbnail_score.good_clipping = statement.ColumnBool(6);
@@ -107,7 +106,7 @@ void TopSitesDatabaseImpl::SetRedirects(const std::string& redirects,
 
 void TopSitesDatabaseImpl::SetPageThumbnail(const MostVisitedURL& url,
                                             int new_rank,
-                                            const Images& thumbnail) {
+                                            const TopSites::Images& thumbnail) {
   sql::Transaction transaction(&db_);
   transaction.Begin();
 
@@ -123,7 +122,7 @@ void TopSitesDatabaseImpl::SetPageThumbnail(const MostVisitedURL& url,
 }
 
 void TopSitesDatabaseImpl::UpdatePageThumbnail(
-    const MostVisitedURL& url, const Images& thumbnail) {
+    const MostVisitedURL& url, const TopSites::Images& thumbnail) {
   sql::Statement statement(db_.GetCachedStatement(
       SQL_FROM_HERE,
       "UPDATE thumbnails SET "
@@ -151,7 +150,7 @@ void TopSitesDatabaseImpl::UpdatePageThumbnail(
 
 void TopSitesDatabaseImpl::AddPageThumbnail(const MostVisitedURL& url,
                                             int new_rank,
-                                            const Images& thumbnail) {
+                                            const TopSites::Images& thumbnail) {
   int count = GetRowCount();
 
   sql::Statement statement(db_.GetCachedStatement(
@@ -195,7 +194,7 @@ void TopSitesDatabaseImpl::UpdatePageRankNoTransaction(
     const MostVisitedURL& url, int new_rank) {
   int prev_rank = GetURLRank(url);
   if (prev_rank == -1) {
-    LOG(WARNING) << "Updating rank of an unknown URL: " << url.url.spec();
+    NOTREACHED() << "Updating rank of an unknown URL: " << url.url.spec();
     return;
   }
 
@@ -237,7 +236,7 @@ void TopSitesDatabaseImpl::UpdatePageRankNoTransaction(
 }
 
 bool TopSitesDatabaseImpl::GetPageThumbnail(const GURL& url,
-                                            Images* thumbnail) {
+                                            TopSites::Images* thumbnail) {
   sql::Statement statement(db_.GetCachedStatement(
       SQL_FROM_HERE,
       "SELECT thumbnail, boring_score, good_clipping, at_top, last_updated "
diff --git a/chrome/browser/history/top_sites_database.h b/chrome/browser/history/top_sites_database.h
index 11188a7..18ec201 100644
--- a/chrome/browser/history/top_sites_database.h
+++ b/chrome/browser/history/top_sites_database.h
@@ -12,12 +12,13 @@
 
 #include "app/sql/connection.h"
 #include "base/ref_counted.h"
+#include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/url_database.h"  // For DBCloseScoper.
 
 class FilePath;
 class RefCountedMemory;
 class SkBitmap;
-class Images;
+class TopSites;
 
 namespace base {
 class Time;
@@ -37,7 +38,7 @@ class TopSitesDatabase {
   // Returns a list of all URLs currently in the table.
   virtual void GetPageThumbnails(MostVisitedURLList* urls,
                                  std::map<GURL,
-                                 Images>* thumbnails) = 0;
+                                 TopSites::Images>* thumbnails) = 0;
 
   // Set a thumbnail for a URL. |url_rank| is the position of the URL
   // in the list of TopURLs, zero-based.
@@ -45,20 +46,20 @@ class TopSitesDatabase {
   // thumbnail.
   virtual void SetPageThumbnail(const MostVisitedURL& url,
                                 int url_rank,
-                                const Images& thumbnail) = 0;
+                                const TopSites::Images& thumbnail) = 0;
 
   // Update rank of a URL that's already in the database.
   virtual void UpdatePageRank(const MostVisitedURL& url, int new_rank) = 0;
 
   // Convenience wrapper.
   bool GetPageThumbnail(const MostVisitedURL& url,
-                        Images* thumbnail) {
+                        TopSites::Images* thumbnail) {
     return GetPageThumbnail(url.url, thumbnail);
   }
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   virtual bool GetPageThumbnail(const GURL& url,
-                                Images* thumbnail) = 0;
+                                TopSites::Images* thumbnail) = 0;
 
   // Remove the record for this URL. Returns true iff removed successfully.
   virtual bool RemoveURL(const MostVisitedURL& url) = 0;
@@ -78,7 +79,7 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
   // Returns a list of all URLs currently in the table.
   // WARNING: clears both input arguments.
   virtual void GetPageThumbnails(MostVisitedURLList* urls,
-                                 std::map<GURL, Images>* thumbnails);
+                                 std::map<GURL, TopSites::Images>* thumbnails);
 
   // Set a thumbnail for a URL. |url_rank| is the position of the URL
   // in the list of TopURLs, zero-based.
@@ -86,7 +87,7 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
   // thumbnail and rank. Shift the ranks of other URLs if necessary.
   virtual void SetPageThumbnail(const MostVisitedURL& url,
                                 int new_rank,
-                                const Images& thumbnail);
+                                const TopSites::Images& thumbnail);
 
   // Sets the rank for a given URL. The URL must be in the database.
   // Use SetPageThumbnail if it's not.
@@ -94,7 +95,7 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   virtual bool GetPageThumbnail(const GURL& url,
-                                Images* thumbnail);
+                                TopSites::Images* thumbnail);
 
   // Remove the record for this URL. Returns true iff removed successfully.
   virtual bool RemoveURL(const MostVisitedURL& url);
@@ -107,14 +108,14 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
   // Adds a new URL to the database.
   void AddPageThumbnail(const MostVisitedURL& url,
                         int new_rank,
-                        const Images& thumbnail);
+                        const TopSites::Images& thumbnail);
 
   // Sets the page rank. Should be called within an open transaction.
   void UpdatePageRankNoTransaction(const MostVisitedURL& url, int new_rank);
 
   // Updates thumbnail of a URL that's already in the database.
   void UpdatePageThumbnail(const MostVisitedURL& url,
-                           const Images& thumbnail);
+                           const TopSites::Images& thumbnail);
 
   // Returns the URL's current rank or -1 if it is not present.
   int GetURLRank(const MostVisitedURL& url);
diff --git a/chrome/browser/history/top_sites_unittest.cc b/chrome/browser/history/top_sites_unittest.cc
index f8ebf95..94db4f2 100644
--- a/chrome/browser/history/top_sites_unittest.cc
+++ b/chrome/browser/history/top_sites_unittest.cc
@@ -74,7 +74,7 @@ class TopSitesTest : public testing::Test {
 
   virtual void TearDown() {
     profile_.reset();
-    TopSites::DeleteTopSites(top_sites_);
+    top_sites_ = NULL;
     EXPECT_TRUE(file_util::Delete(file_name_, false));
   }
 
@@ -92,6 +92,7 @@ class TopSitesTest : public testing::Test {
   }
 
   void StoreMostVisited(std::vector<MostVisitedURL>* urls) {
+    AutoLock lock(top_sites_->lock_);  // The function asserts it's in the lock.
     top_sites_->StoreMostVisited(urls);
   }
 
@@ -104,10 +105,6 @@ class TopSitesTest : public testing::Test {
                               added_urls, deleted_urls, moved_urls);
   }
 
-  Lock& lock() {
-    return top_sites_->lock_;
-  }
-
  private:
   scoped_refptr<TopSites> top_sites_;
   MostVisitedURLList urls_;
@@ -124,7 +121,6 @@ class TopSitesTest : public testing::Test {
   DISALLOW_COPY_AND_ASSIGN(TopSitesTest);
 };
 
-
 // A mockup of a HistoryService used for testing TopSites.
 class MockHistoryServiceImpl : public TopSites::MockHistoryService {
  public:
@@ -192,14 +188,14 @@ class MockHistoryServiceImpl : public TopSites::MockHistoryService {
 class MockTopSitesDatabaseImpl : public TopSitesDatabase {
  public:
   virtual void GetPageThumbnails(MostVisitedURLList* urls,
-                                 std::map<GURL, Images>* thumbnails) {
+                                 std::map<GURL, TopSites::Images>* thumbnails) {
     // Return a copy of the vector.
     *urls = top_sites_list_;
     *thumbnails = thumbnails_map_;
   }
 
   virtual void SetPageThumbnail(const MostVisitedURL& url, int url_rank,
-                                const Images& thumbnail) {
+                                const TopSites::Images& thumbnail) {
     SetPageRank(url, url_rank);
     // Update thubmnail
     thumbnails_map_[url.url] = thumbnail;
@@ -233,8 +229,8 @@ class MockTopSitesDatabaseImpl : public TopSitesDatabase {
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   virtual bool GetPageThumbnail(const GURL& url,
-                                Images* thumbnail) {
-    std::map<GURL, Images>::const_iterator found =
+                                TopSites::Images* thumbnail) {
+    std::map<GURL, TopSites::Images>::const_iterator found =
         thumbnails_map_.find(url);
     if (found == thumbnails_map_.end())
       return false;  // No thumbnail for this URL.
@@ -259,7 +255,7 @@ class MockTopSitesDatabaseImpl : public TopSitesDatabase {
 
  private:
   MostVisitedURLList top_sites_list_;  // Keeps the URLs sorted by score (rank).
-  std::map<GURL, Images> thumbnails_map_;
+  std::map<GURL, TopSites::Images> thumbnails_map_;
 };
 
 
@@ -452,7 +448,7 @@ TEST_F(TopSitesTest, MockDatabase) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  Images thumbnail;
+  TopSites::Images thumbnail;
   db->SetPageThumbnail(url, 0, thumbnail);
 
   top_sites().ReadDatabase();
@@ -499,7 +495,7 @@ TEST_F(TopSitesTest, MockDatabase) {
   top_sites().StartQueryForMostVisited();
   MessageLoop::current()->RunAllPending();
 
-  std::map<GURL, Images> thumbnails;
+  std::map<GURL, TopSites::Images> thumbnails;
   MostVisitedURLList result;
   db->GetPageThumbnails(&result, &thumbnails);
   ASSERT_EQ(4u, result.size());
@@ -524,18 +520,18 @@ TEST_F(TopSitesTest, TopSitesDB) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  Images thumbnail;
+  TopSites::Images thumbnail;
   thumbnail.thumbnail = random_thumbnail();
   // Add asdf at rank 0.
   db.SetPageThumbnail(url, 0, thumbnail);
 
-  Images result;
+  TopSites::Images result;
   EXPECT_TRUE(db.GetPageThumbnail(url.url, &result));
   EXPECT_EQ(thumbnail.thumbnail->data.size(), result.thumbnail->data.size());
   EXPECT_TRUE(ThumbnailsAreEqual(thumbnail.thumbnail, result.thumbnail));
 
   MostVisitedURLList urls;
-  std::map<GURL, Images> thumbnails;
+  std::map<GURL, TopSites::Images> thumbnails;
   db.GetPageThumbnails(&urls, &thumbnails);
   ASSERT_EQ(1u, urls.size());
   EXPECT_EQ(asdf_url, urls[0].url);
@@ -611,7 +607,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  Images thumbnail;
+  TopSites::Images thumbnail;
   thumbnail.thumbnail = random_thumbnail();
   db->SetPageThumbnail(url, 0, thumbnail);
 
@@ -627,7 +623,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   EXPECT_EQ(welcome_url(), urls()[1].url);
   EXPECT_EQ(themes_url(), urls()[2].url);
 
-  Images img_result;
+  TopSites::Images img_result;
   db->GetPageThumbnail(asdf_url, &img_result);
   EXPECT_TRUE(img_result.thumbnail != NULL);
   EXPECT_TRUE(ThumbnailsAreEqual(random_thumbnail(), img_result.thumbnail));
@@ -645,7 +641,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   url2.redirects.push_back(google3_url);
 
   // Add new thumbnail at rank 0 and shift the other result to 1.
-  Images g_thumbnail;
+  TopSites::Images g_thumbnail;
   g_thumbnail.thumbnail = google_thumbnail();
   db->SetPageThumbnail(url2, 0, g_thumbnail);
 
@@ -680,7 +676,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   top_sites().StartQueryForMostVisited();
   MessageLoop::current()->RunAllPending();
 
-  std::map<GURL, Images> thumbnails;
+  std::map<GURL, TopSites::Images> thumbnails;
   MostVisitedURLList results;
   db->GetPageThumbnails(&results, &thumbnails);
   ASSERT_EQ(4u, results.size());
@@ -701,7 +697,7 @@ TEST_F(TopSitesTest, RealDatabase) {
                                            *weewar_bitmap,
                                            medium_score));
   RefCountedBytes* out_1;
-  Images out_2;
+  TopSites::Images out_2;
   EXPECT_TRUE(top_sites().GetPageThumbnail(google1_url, &out_1));
 
   MessageLoop::current()->RunAllPending();
@@ -1078,11 +1074,7 @@ TEST_F(TopSitesTest, Blacklisting) {
                   &TopSitesTest::OnTopSitesAvailable));
   top_sites().OnTopSitesAvailable(0, pages);
   MessageLoop::current()->RunAllPending();
-  {
-    Lock& l = lock();
-    AutoLock lock(l);  // IsBlacklisted must be in a lock.
-    EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
-  }
+  EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
 
   EXPECT_EQ(1u, number_of_callbacks());
 
@@ -1093,13 +1085,9 @@ TEST_F(TopSitesTest, Blacklisting) {
   EXPECT_EQ(themes_url(), urls()[3].url);
 
   top_sites().AddBlacklistedURL(GURL("http://google.com/"));
-  {
-    Lock& l = lock();
-    AutoLock lock(l);  // IsBlacklisted must be in a lock.
-    EXPECT_TRUE(top_sites().IsBlacklisted(GURL("http://google.com/")));
-    EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
-    EXPECT_FALSE(top_sites().IsBlacklisted(welcome_url()));
-  }
+  EXPECT_TRUE(top_sites().IsBlacklisted(GURL("http://google.com/")));
+  EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
+  EXPECT_FALSE(top_sites().IsBlacklisted(welcome_url()));
 
   top_sites().GetMostVisitedURLs(
       &c,
@@ -1122,11 +1110,7 @@ TEST_F(TopSitesTest, Blacklisting) {
   EXPECT_EQ(themes_url(), urls()[1].url);
 
   top_sites().RemoveBlacklistedURL(GURL("http://google.com/"));
-  {
-    Lock& l = lock();
-    AutoLock lock(l);  // IsBlacklisted must be in a lock.
-    EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://google.com/")));
-  }
+  EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://google.com/")));
 
   top_sites().GetMostVisitedURLs(
       &c,
@@ -1167,6 +1151,7 @@ TEST_F(TopSitesTest, PinnedURLs) {
                   &TopSitesTest::OnTopSitesAvailable));
   top_sites().OnTopSitesAvailable(0, pages);
   MessageLoop::current()->RunAllPending();
+  size_t index = 0;
   EXPECT_FALSE(top_sites().IsURLPinned(GURL("http://bbc.com/")));
 
   ASSERT_EQ(4u, urls().size());
@@ -1176,6 +1161,9 @@ TEST_F(TopSitesTest, PinnedURLs) {
   EXPECT_EQ(themes_url(), urls()[3].url);
 
   top_sites().AddPinnedURL(GURL("http://google.com/"), 3);
+  EXPECT_TRUE(top_sites().GetIndexOfPinnedURL(GURL("http://google.com/"),
+                                              &index));
+  EXPECT_EQ(3u, index);
   EXPECT_FALSE(top_sites().IsURLPinned(GURL("http://bbc.com/")));
   EXPECT_FALSE(top_sites().IsURLPinned(welcome_url()));
 
diff --git a/chrome/browser/profile_impl.cc b/chrome/browser/profile_impl.cc
index 62e50d5..bb335bf 100644
--- a/chrome/browser/profile_impl.cc
+++ b/chrome/browser/profile_impl.cc
@@ -498,8 +498,6 @@ ProfileImpl::~ProfileImpl() {
 
   // This causes the Preferences file to be written to disk.
   MarkAsCleanShutdown();
-  if (top_sites_.get())
-    top_sites_->ClearProfile();
 }
 
 ProfileId ProfileImpl::GetRuntimeId() {
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 866da5a..2992612 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -2418,7 +2418,7 @@ void TabContents::UpdateThumbnail(const GURL& url,
                                   const SkBitmap& bitmap,
                                   const ThumbnailScore& score) {
   // Tell History about this thumbnail
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
     if (!profile()->IsOffTheRecord())
       profile()->GetTopSites()->SetPageThumbnail(url, bitmap, score);
   } else {
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 111dc88..454fffd 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -682,9 +682,6 @@ const char kNoProxyServer[]                 = "no-proxy-server";
 // Runs the renderer outside the sandbox.
 const char kNoSandbox[]                     = "no-sandbox";
 
-// Don't use TopSites; use old ThumbnailDatabase code instead.
-const char kNoTopSites[]                    = "no-top-sites";
-
 // Specifies the maximum number of threads to use for running the Proxy
 // Autoconfig (PAC) script.
 const char kNumPacThreads[]                 = "num-pac-threads";
@@ -945,6 +942,10 @@ const char kTestType[]                      = "test-type";
 // testing-related messages on IPC channel with the given ID.
 const char kTestingChannelID[]              = "testing-channel";
 
+// Enables using TopSites instead of ThumbnailDatabase (and
+// ThumbnailStore) for getting thumbnails for the new tab page.
+const char kTopSites[]                      = "top-sites";
+
 // Excludes these plugins from the plugin sandbox.
 // This is a comma-separated list of plugin library names.
 const char kTrustedPlugins[]                = "trusted-plugins";
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 1e660dd..cc69770 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -201,7 +201,6 @@ extern const char kNoJsRandomness[];
 extern const char kNoProxyServer[];
 extern const char kNoReferrers[];
 extern const char kNoSandbox[];
-extern const char kNoTopSites[];
 extern const char kNumPacThreads[];
 extern const char kOpenInNewWindow[];
 extern const char kOrganicInstall[];
@@ -270,6 +269,7 @@ extern const char kTestName[];
 extern const char kTestSandbox[];
 extern const char kTestType[];
 extern const char kTestingChannelID[];
+extern const char kTopSites[];
 extern const char kTrustedPlugins[];
 extern const char kTryChromeAgain[];
 extern const char kUninstall[];
diff --git a/chrome/test/data/profiles/typical_history/Default/History b/chrome/test/data/profiles/typical_history/Default/History
index cf186c9..98481ce 100644
--- a/chrome/test/data/profiles/typical_history/Default/History
+++ b/chrome/test/data/profiles/typical_history/Default/History
diff --git a/chrome/test/testing_profile.cc b/chrome/test/testing_profile.cc
index 48d2e51..547aff0 100644
--- a/chrome/test/testing_profile.cc
+++ b/chrome/test/testing_profile.cc
@@ -178,10 +178,6 @@ TestingProfile::~TestingProfile() {
   // FaviconService depends on HistoryServce so destroying it later.
   DestroyFaviconService();
   DestroyWebDataService();
-  history::TopSites::DeleteTopSites(top_sites_);
-  if (top_sites_.get())
-    top_sites_->ClearProfile();
-
   file_util::Delete(path_, true);
 }
 
diff --git a/chrome/test/testing_profile.h b/chrome/test/testing_profile.h
index dd8976e..36f638f 100644
--- a/chrome/test/testing_profile.h
+++ b/chrome/test/testing_profile.h
@@ -9,7 +9,6 @@
 #include "base/base_paths.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
-#include "base/scoped_temp_dir.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/browser_prefs.h"
@@ -21,7 +20,6 @@
 #include "chrome/browser/geolocation/geolocation_permission_context.h"
 #include "chrome/browser/host_content_settings_map.h"
 #include "chrome/browser/history/history.h"
-#include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/in_process_webkit/webkit_context.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/pref_service.h"
@@ -165,16 +163,7 @@ class TestingProfile : public Profile {
     return template_url_model_.get();
   }
   virtual TemplateURLFetcher* GetTemplateURLFetcher() { return NULL; }
-  virtual history::TopSites* GetTopSites() {
-    if (!top_sites_.get()) {
-      top_sites_ = new history::TopSites(this);
-      if (!temp_dir_.CreateUniqueTempDir())
-        return NULL;
-      FilePath file_name = temp_dir_.path().AppendASCII("TopSites.db");
-      top_sites_->Init(file_name);
-    }
-    return top_sites_;
-  }
+  virtual history::TopSites* GetTopSites() { return NULL; }
   virtual DownloadManager* GetDownloadManager() { return NULL; }
   virtual PersonalDataManager* GetPersonalDataManager() { return NULL; }
   virtual bool HasCreatedDownloadManager() const { return false; }
@@ -383,8 +372,6 @@ class TestingProfile : public Profile {
   scoped_ptr<FindBarState> find_bar_state_;
 
   FilePath last_selected_directory_;
-  scoped_refptr<history::TopSites> top_sites_;  // For history and thumbnails.
-  ScopedTempDir temp_dir_;
 };
 
 // A profile that derives from another profile.  This does not actually