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

BUG=none
TEST=manual

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=55244

Review URL: http://codereview.chromium.org/3054028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55610 0039d316-1c4b-4281-b951-d872f2087c98

18 files changed, 304 insertions, 152 deletions

diff --git a/chrome/browser/chrome_thread.h b/chrome/browser/chrome_thread.h
index c3d6f97..3831b7c 100644
--- a/chrome/browser/chrome_thread.h
+++ b/chrome/browser/chrome_thread.h
@@ -165,7 +165,7 @@ class ChromeThread : public base::Thread {
   //
   // ...
   //  private:
-  //   friend class ChromeThread;
+  //   friend struct ChromeThread::DeleteOnThread<ChromeThread::IO>;
   //   friend class DeleteTask<Foo>;
   //
   //   ~Foo();
diff --git a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
index fd6eae7..ebff335 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::kTopSites)) {
-    scoped_refptr<history::TopSites> top_sites = profile_->GetTopSites();
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
+    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 1670ac3..be9f9c5 100644
--- a/chrome/browser/dom_ui/most_visited_handler.cc
+++ b/chrome/browser/dom_ui/most_visited_handler.cc
@@ -151,7 +151,7 @@ void MostVisitedHandler::SendPagesValue() {
 }
 
 void MostVisitedHandler::StartQueryForMostVisited() {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     // Use TopSites.
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->GetMostVisitedURLs(
@@ -213,7 +213,7 @@ void MostVisitedHandler::HandleRemoveURLsFromBlacklist(const Value* urls) {
     }
     UserMetrics::RecordAction(UserMetricsAction("MostVisited_UrlRemoved"),
                               dom_ui_->GetProfile());
-    if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+    if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
       history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
       ts->RemoveBlacklistedURL(GURL(url));
       return;
@@ -228,7 +228,7 @@ void MostVisitedHandler::HandleClearBlacklist(const Value* value) {
   UserMetrics::RecordAction(UserMetricsAction("MostVisited_BlacklistCleared"),
                             dom_ui_->GetProfile());
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->ClearBlacklistedURLs();
     return;
@@ -278,7 +278,7 @@ void MostVisitedHandler::HandleAddPinnedURL(const Value* value) {
 }
 
 void MostVisitedHandler::AddPinnedURL(const MostVisitedPage& page, int index) {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->AddPinnedURL(page.url, index);
     return;
@@ -317,7 +317,7 @@ void MostVisitedHandler::HandleRemovePinnedURL(const Value* value) {
 }
 
 void MostVisitedHandler::RemovePinnedURL(const GURL& url) {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     history::TopSites* ts = dom_ui_->GetProfile()->GetTopSites();
     ts->RemovePinnedURL(url);
     return;
@@ -487,7 +487,7 @@ void MostVisitedHandler::SetPagesValue(std::vector<PageUsageData*>* data) {
 
 void MostVisitedHandler::SetPagesValueFromTopSites(
     const history::MostVisitedURLList& data) {
-  DCHECK(CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites));
+  DCHECK(!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites));
   pages_value_.reset(new ListValue);
   for (size_t i = 0; i < data.size(); i++) {
     const history::MostVisitedURL& url = data[i];
@@ -608,7 +608,7 @@ void MostVisitedHandler::Observe(NotificationType type,
 }
 
 void MostVisitedHandler::BlacklistURL(const GURL& url) {
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     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 ca822bc..95b391f 100644
--- a/chrome/browser/history/expire_history_backend_unittest.cc
+++ b/chrome/browser/history/expire_history_backend_unittest.cc
@@ -16,8 +16,10 @@
 #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"
@@ -90,6 +92,8 @@ 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_;
@@ -134,6 +138,7 @@ 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() {
@@ -145,6 +150,7 @@ class ExpireHistoryTest : public testing::Test,
     archived_db_.reset();
     thumb_db_.reset();
     text_db_.reset();
+    TopSites::DeleteTopSites(top_sites_);
     file_util::Delete(dir_, true);
   }
 
@@ -211,9 +217,9 @@ void ExpireHistoryTest::AddExampleData(URLID url_ids[3], Time visit_times[4]) {
 
   Time time;
   GURL gurl;
-  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);
+  top_sites_->SetPageThumbnail(url_row1.url(), *thumbnail, score);
+  top_sites_->SetPageThumbnail(url_row2.url(), *thumbnail, score);
+  top_sites_->SetPageThumbnail(url_row3.url(), *thumbnail, score);
 
   // Four visits.
   VisitRow visit_row1;
@@ -271,8 +277,12 @@ bool ExpireHistoryTest::HasFavIcon(FavIconID favicon_id) {
 }
 
 bool ExpireHistoryTest::HasThumbnail(URLID url_id) {
-  std::vector<unsigned char> temp_data;
-  return thumb_db_->GetPageThumbnail(url_id, &temp_data);
+  URLRow info;
+  if (!main_db_->GetURLRow(url_id, &info))
+    return false;
+  GURL url = info.url();
+  RefCountedBytes *data;
+  return top_sites_->GetPageThumbnail(url, &data);
 }
 
 int ExpireHistoryTest::CountTextMatchesForURL(const GURL& url) {
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 8e1c5fb..1c58f74 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::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     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::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     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 24cc1cd..780038d 100644
--- a/chrome/browser/history/history_backend_unittest.cc
+++ b/chrome/browser/history/history_backend_unittest.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -13,6 +14,7 @@
 #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"
@@ -402,6 +404,9 @@ 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";
@@ -598,6 +603,9 @@ 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 26bb81a..7869fcc 100644
--- a/chrome/browser/history/history_database.cc
+++ b/chrome/browser/history/history_database.cc
@@ -134,14 +134,11 @@ void HistoryDatabase::BeginExclusiveMode() {
 
 // static
 int HistoryDatabase::GetCurrentVersion() {
-  // 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)) {
+  // 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
     return kCurrentVersionNumber;
-  } else {
-    return kCurrentVersionNumber - 1;
-  }
 }
 
 void HistoryDatabase::BeginTransaction() {
@@ -286,7 +283,7 @@ sql::InitStatus HistoryDatabase::EnsureCurrentVersion(
   if (cur_version == 17)
     needs_version_18_migration_ = true;
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites) &&
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites) &&
       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 0c283b1..21e8067 100644
--- a/chrome/browser/history/history_types.h
+++ b/chrome/browser/history/history_types.h
@@ -13,12 +13,14 @@
 #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 {
@@ -527,6 +529,15 @@ 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 c8db05a..063414f 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -24,6 +24,7 @@
 #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"
@@ -41,6 +42,7 @@
 #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"
@@ -685,6 +687,9 @@ 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 8bf203d..979accf 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::kTopSites)) {
+    if (!CommandLine::ForCurrentProcess()-> HasSwitch(switches::kNoTopSites)) {
       use_top_sites_ = true;
       return true;
     }
@@ -231,8 +231,10 @@ void ThumbnailDatabase::SetPageThumbnail(
     const SkBitmap& thumbnail,
     const ThumbnailScore& score,
     base::Time time) {
-  if (use_top_sites_)
+  if (use_top_sites_) {
+    LOG(WARNING) << "Use TopSites instead.";
     return;  // Not possible after migration to TopSites.
+  }
 
   if (!thumbnail.isNull()) {
     bool add_thumbnail = true;
@@ -286,8 +288,10 @@ void ThumbnailDatabase::SetPageThumbnail(
 
 bool ThumbnailDatabase::GetPageThumbnail(URLID id,
                                          std::vector<unsigned char>* data) {
-  if (use_top_sites_)
+  if (use_top_sites_) {
+    LOG(WARNING) << "Use TopSites instead.";
     return false;  // Not possible after migration to TopSites.
+  }
 
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "SELECT data FROM thumbnails WHERE url_id=?"));
@@ -303,8 +307,10 @@ bool ThumbnailDatabase::GetPageThumbnail(URLID id,
 }
 
 bool ThumbnailDatabase::DeleteThumbnail(URLID id) {
-  if (use_top_sites_)
+  if (use_top_sites_) {
+    LOG(WARNING) << "Use TopSites instead.";
     return true;  // Not possible after migration to TopSites.
+  }
 
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "DELETE FROM thumbnails WHERE url_id = ?"));
@@ -317,8 +323,10 @@ bool ThumbnailDatabase::DeleteThumbnail(URLID id) {
 
 bool ThumbnailDatabase::ThumbnailScoreForId(URLID id,
                                             ThumbnailScore* score) {
-  if (use_top_sites_)
+  if (use_top_sites_) {
+    LOG(WARNING) << "Use TopSites instead.";
     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 4d2c2bf..24c990b 100644
--- a/chrome/browser/history/thumbnail_database_unittest.cc
+++ b/chrome/browser/history/thumbnail_database_unittest.cc
@@ -6,6 +6,7 @@
 #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"
@@ -13,6 +14,7 @@
 #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"
@@ -70,6 +72,9 @@ 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));
 
@@ -112,6 +117,9 @@ 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));
@@ -146,6 +154,9 @@ 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));
@@ -217,6 +228,9 @@ 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);
@@ -261,6 +275,9 @@ 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));
@@ -332,6 +349,9 @@ 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 a7e5deb..d1b349c 100644
--- a/chrome/browser/history/top_sites.cc
+++ b/chrome/browser/history/top_sites.cc
@@ -54,10 +54,15 @@ TopSites::TopSites(Profile* profile) : profile_(profile),
                                        waiting_for_results_(true),
                                        blacklist_(NULL),
                                        pinned_urls_(NULL) {
-  registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
-                 Source<Profile>(profile_));
-  registrar_.Add(this, NotificationType::NAV_ENTRY_COMMITTED,
-                 NotificationService::AllSources());
+  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());
+  }
 
   blacklist_ = profile_->GetPrefs()->
       GetMutableDictionary(prefs::kNTPMostVisitedURLsBlacklist);
@@ -90,16 +95,14 @@ void TopSites::ReadDatabase() {
   std::map<GURL, Images> thumbnails;
 
   DCHECK(db_.get());
-  {
-    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.
+  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_);
   for (size_t i = 0; i < top_sites_.size(); i++) {
     GURL url = top_sites_[i].url;
     Images thumbnail = thumbnails[url];
@@ -145,12 +148,14 @@ bool TopSites::SetPageThumbnail(const GURL& url,
     return true;
   }
 
-  return SetPageThumbnail(url, thumbnail_data, score);
+  AutoLock lock(lock_);
+  return SetPageThumbnailEncoded(url, thumbnail_data, score);
 }
 
-bool TopSites::SetPageThumbnail(const GURL& url,
-                                const RefCountedBytes* thumbnail,
-                                const ThumbnailScore& score) {
+bool TopSites::SetPageThumbnailEncoded(const GURL& url,
+                                       const RefCountedBytes* thumbnail,
+                                       const ThumbnailScore& score) {
+  lock_.AssertAcquired();
   if (!SetPageThumbnailNoDB(url, thumbnail, score))
     return false;
 
@@ -171,7 +176,7 @@ bool TopSites::SetPageThumbnail(const GURL& url,
 
 void TopSites::WriteThumbnailToDB(const MostVisitedURL& url,
                                   int url_rank,
-                                  const TopSites::Images& thumbnail) {
+                                  const Images& thumbnail) {
   DCHECK(db_.get());
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::DB));
   db_->SetPageThumbnail(url, url_rank, thumbnail);
@@ -181,7 +186,7 @@ void TopSites::WriteThumbnailToDB(const MostVisitedURL& url,
 bool TopSites::SetPageThumbnailNoDB(const GURL& url,
                                     const RefCountedBytes* thumbnail_data,
                                     const ThumbnailScore& score) {
-  AutoLock lock(lock_);
+  lock_.AssertAcquired();
 
   std::map<GURL, size_t>::iterator found = canonical_urls_.find(url);
   if (found == canonical_urls_.end()) {
@@ -237,15 +242,21 @@ void TopSites::GetMostVisitedURLs(CancelableRequestConsumer* consumer,
     return;
 
   MostVisitedURLList filtered_urls;
-  ApplyBlacklistAndPinnedURLs(top_sites_, &filtered_urls);
-
+  {
+    AutoLock lock(lock_);
+    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())
-    return false;  // No thumbnail for this 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.
+  }
 
   Images image = found->second;
   *data = image.thumbnail.get();
@@ -262,8 +273,11 @@ static int IndexOf(const MostVisitedURLList& urls, const GURL& url) {
 
 int TopSites::GetIndexForChromeStore(const MostVisitedURLList& urls) {
   GURL store_url = MostVisitedHandler::GetChromeStoreURLWithLocale();
-  if (IsBlacklisted(store_url))
-    return -1;
+  {
+    AutoLock lock(lock_);
+    if (IsBlacklisted(store_url))
+      return -1;
+  }
 
   if (IndexOf(urls, store_url) != -1)
     return -1;  // It's already there, no need to add.
@@ -290,6 +304,9 @@ 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;
@@ -371,6 +388,7 @@ 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]);
@@ -417,10 +435,12 @@ 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()));
 }
 
@@ -430,27 +450,33 @@ 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();
 
-  // 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);
+  {
+    AutoLock lock(lock_);
 
-    // Delete from disk.
-    if (db_.get())
-      db_->RemoveURL(deleted_url);
+    // 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);
+    }
   }
 
+  // Write the updates to the DB.
   if (db_.get()) {
-    // Write both added and moved urls.
+    for (size_t i = 0; i < deleted.size(); i++) {
+      const MostVisitedURL& deleted_url = top_sites_[deleted[i]];
+      if (db_.get())
+        db_->RemoveURL(deleted_url);
+    }
     for (size_t i = 0; i < added.size(); i++) {
       const MostVisitedURL& added_url = most_visited[added[i]];
       db_->SetPageThumbnail(added_url, added[i], Images());
@@ -484,6 +510,9 @@ 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)
@@ -521,6 +550,9 @@ 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)
@@ -533,6 +565,7 @@ 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];
@@ -542,8 +575,9 @@ void TopSites::GenerateCanonicalURLs() {
 
 void TopSites::StoreMostVisited(MostVisitedURLList* most_visited) {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::DB));
-  // Take ownership of the most visited data.
+  AutoLock lock(lock_);
   top_sites_.clear();
+  // Take ownership of the most visited data.
   top_sites_.swap(*most_visited);
   waiting_for_results_ = false;
 
@@ -560,8 +594,8 @@ 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)) {
-        SetPageThumbnail(mv.url, it->second.thumbnail,
-                         it->second.thumbnail_score);
+        SetPageThumbnailEncoded(mv.url, it->second.thumbnail,
+                                it->second.thumbnail_score);
         temp_thumbnails_map_.erase(it);
         break;
       }
@@ -584,6 +618,7 @@ 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.
@@ -652,6 +687,9 @@ 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) {
@@ -667,23 +705,27 @@ void TopSites::StartQueryForMostVisited() {
 }
 
 void TopSites::StartMigration() {
+  LOG(INFO) << "Starting migration to TopSites.";
   migration_in_progress_ = true;
   StartQueryForMostVisited();
   MigratePinnedURLs();
 }
 
 void TopSites::AddBlacklistedURL(const GURL& url) {
-  RemovePinnedURL(url);
+  AutoLock lock(lock_);
+  RemovePinnedURLLocked(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);
 }
 
@@ -702,22 +744,22 @@ 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) {
-  pinned_urls_->RemoveWithoutPathExpansion(GetURLString(url), NULL);
+  AutoLock lock(lock_);
+  RemovePinnedURLLocked(url);
 }
 
-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;
+void TopSites::RemovePinnedURLLocked(const GURL& url) {
+  lock_.AssertAcquired();
+  pinned_urls_->RemoveWithoutPathExpansion(GetURLString(url), NULL);
 }
 
 bool TopSites::IsURLPinned(const GURL& url) {
+  AutoLock lock(lock_);
   int tmp;
   bool result = pinned_urls_->GetIntegerWithoutPathExpansion(
       GetURLString(url), &tmp);
@@ -738,6 +780,24 @@ 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);
@@ -758,7 +818,10 @@ void TopSites::OnTopSitesAvailable(
 
   if (!pending_callbacks_.empty()) {
     MostVisitedURLList filtered_urls;
-    ApplyBlacklistAndPinnedURLs(pages, &filtered_urls);
+    {
+      AutoLock lock(lock_);
+      ApplyBlacklistAndPinnedURLs(pages, &filtered_urls);
+    }
 
     PendingCallbackSet::iterator i;
     for (i = pending_callbacks_.begin();
@@ -777,7 +840,12 @@ void TopSites::OnThumbnailAvailable(CancelableRequestProvider::Handle handle,
   if (mock_history_service_) {
     index = handle;
   } else {
+    if (!profile_)
+      return;
+
     HistoryService* hs = profile_ ->GetHistoryService(Profile::EXPLICIT_ACCESS);
+    if (!hs)
+      return;
     index = cancelable_consumer_.GetClientData(hs, handle);
   }
   DCHECK(static_cast<size_t>(index) < top_sites_.size());
@@ -787,7 +855,8 @@ void TopSites::OnThumbnailAvailable(CancelableRequestProvider::Handle handle,
 
   if (thumbnail.get() && thumbnail->size()) {
     const MostVisitedURL& url = top_sites_[index];
-    SetPageThumbnail(url.url, thumbnail, ThumbnailScore());
+    AutoLock lock(lock_);
+    SetPageThumbnailEncoded(url.url, thumbnail, ThumbnailScore());
   }
 
   if (migration_in_progress_ && migration_pending_urls_.empty() &&
@@ -803,6 +872,7 @@ 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();
@@ -821,7 +891,7 @@ 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;
-        RemovePinnedURL(top_sites_[index].url);
+        RemovePinnedURLLocked(top_sites_[index].url);
         top_sites_.erase(top_sites_.begin() + index);
       }
     }
@@ -830,11 +900,14 @@ void TopSites::Observe(NotificationType type,
     StartQueryForMostVisited();
   } else if (type == NotificationType::NAV_ENTRY_COMMITTED) {
     if (top_sites_.size() < kTopSitesNumber) {
-      const NavigationController::LoadCommittedDetails& load_details =
-          *Details<NavigationController::LoadCommittedDetails>(details).ptr();
-      GURL url = load_details.entry->url();
+      NavigationController::LoadCommittedDetails* load_details =
+          Details<NavigationController::LoadCommittedDetails>(details).ptr();
+      if (!load_details)
+        return;
+      GURL url = load_details->entry->url();
       if (canonical_urls_.find(url) == canonical_urls_.end() &&
-           HistoryService::CanAddURL(url)) {
+          HistoryService::CanAddURL(url)) {
+        AutoLock lock(lock_);
         // 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 09d0af0..b460afb 100644
--- a/chrome/browser/history/top_sites.h
+++ b/chrome/browser/history/top_sites.h
@@ -18,6 +18,7 @@
 #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"
@@ -47,9 +48,11 @@ 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 NotificationObserver,
-                 public base::RefCountedThreadSafe<TopSites>,
-                 public CancelableRequestProvider {
+class TopSites :
+      public base::RefCountedThreadSafe<TopSites,
+                                        ChromeThread::DeleteOnUIThread>,
+      public NotificationObserver,
+      public CancelableRequestProvider {
  public:
   explicit TopSites(Profile* profile);
 
@@ -68,14 +71,6 @@ class TopSites : public NotificationObserver,
         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);
 
@@ -108,9 +103,6 @@ class TopSites : public NotificationObserver,
   // 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);
 
@@ -122,9 +114,6 @@ class TopSites : public NotificationObserver,
   // 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);
 
@@ -135,8 +124,18 @@ class TopSites : public NotificationObserver,
   // 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 class base::RefCountedThreadSafe<TopSites>;
+  friend struct ChromeThread::DeleteOnThread<ChromeThread::UI>;
+  friend class DeleteTask<TopSites>;
   friend class TopSitesTest;
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, GetMostVisited);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, RealDatabase);
@@ -165,9 +164,9 @@ class TopSites : public NotificationObserver,
 
   // A version of SetPageThumbnail that takes RefCountedBytes as
   // returned by HistoryService.
-  bool SetPageThumbnail(const GURL& url,
-                        const RefCountedBytes* thumbnail,
-                        const ThumbnailScore& score);
+  bool SetPageThumbnailEncoded(const GURL& url,
+                               const RefCountedBytes* thumbnail,
+                               const ThumbnailScore& score);
 
   // Query history service for the list of available thumbnails.
   void StartQueryForMostVisited();
@@ -229,6 +228,12 @@ class TopSites : public NotificationObserver,
                        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();
@@ -243,7 +248,7 @@ class TopSites : public NotificationObserver,
   // Write a thumbnail to database.
   void WriteThumbnailToDB(const MostVisitedURL& url,
                           int url_rank,
-                          const TopSites::Images& thumbnail);
+                          const 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 99f0bb4..96da3f9 100644
--- a/chrome/browser/history/top_sites_database.cc
+++ b/chrome/browser/history/top_sites_database.cc
@@ -5,6 +5,7 @@
 #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"
 
@@ -48,7 +49,7 @@ bool TopSitesDatabaseImpl::InitThumbnailTable() {
 
 void TopSitesDatabaseImpl::GetPageThumbnails(MostVisitedURLList* urls,
                                              std::map<GURL,
-                                             TopSites::Images>* thumbnails) {
+                                             Images>* thumbnails) {
   sql::Statement statement(db_.GetCachedStatement(
       SQL_FROM_HERE,
       "SELECT url, url_rank, title, thumbnail, redirects, "
@@ -75,7 +76,7 @@ void TopSitesDatabaseImpl::GetPageThumbnails(MostVisitedURLList* urls,
 
     std::vector<unsigned char> data;
     statement.ColumnBlobAsVector(3, &data);
-    TopSites::Images thumbnail;
+    Images thumbnail;
     thumbnail.thumbnail = RefCountedBytes::TakeVector(&data);
     thumbnail.thumbnail_score.boring_score = statement.ColumnDouble(5);
     thumbnail.thumbnail_score.good_clipping = statement.ColumnBool(6);
@@ -106,7 +107,7 @@ void TopSitesDatabaseImpl::SetRedirects(const std::string& redirects,
 
 void TopSitesDatabaseImpl::SetPageThumbnail(const MostVisitedURL& url,
                                             int new_rank,
-                                            const TopSites::Images& thumbnail) {
+                                            const Images& thumbnail) {
   sql::Transaction transaction(&db_);
   transaction.Begin();
 
@@ -122,7 +123,7 @@ void TopSitesDatabaseImpl::SetPageThumbnail(const MostVisitedURL& url,
 }
 
 void TopSitesDatabaseImpl::UpdatePageThumbnail(
-    const MostVisitedURL& url, const TopSites::Images& thumbnail) {
+    const MostVisitedURL& url, const Images& thumbnail) {
   sql::Statement statement(db_.GetCachedStatement(
       SQL_FROM_HERE,
       "UPDATE thumbnails SET "
@@ -150,7 +151,7 @@ void TopSitesDatabaseImpl::UpdatePageThumbnail(
 
 void TopSitesDatabaseImpl::AddPageThumbnail(const MostVisitedURL& url,
                                             int new_rank,
-                                            const TopSites::Images& thumbnail) {
+                                            const Images& thumbnail) {
   int count = GetRowCount();
 
   sql::Statement statement(db_.GetCachedStatement(
@@ -194,7 +195,7 @@ void TopSitesDatabaseImpl::UpdatePageRankNoTransaction(
     const MostVisitedURL& url, int new_rank) {
   int prev_rank = GetURLRank(url);
   if (prev_rank == -1) {
-    NOTREACHED() << "Updating rank of an unknown URL: " << url.url.spec();
+    LOG(WARNING) << "Updating rank of an unknown URL: " << url.url.spec();
     return;
   }
 
@@ -236,7 +237,7 @@ void TopSitesDatabaseImpl::UpdatePageRankNoTransaction(
 }
 
 bool TopSitesDatabaseImpl::GetPageThumbnail(const GURL& url,
-                                            TopSites::Images* thumbnail) {
+                                            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 18ec201..11188a7 100644
--- a/chrome/browser/history/top_sites_database.h
+++ b/chrome/browser/history/top_sites_database.h
@@ -12,13 +12,12 @@
 
 #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 TopSites;
+class Images;
 
 namespace base {
 class Time;
@@ -38,7 +37,7 @@ class TopSitesDatabase {
   // Returns a list of all URLs currently in the table.
   virtual void GetPageThumbnails(MostVisitedURLList* urls,
                                  std::map<GURL,
-                                 TopSites::Images>* thumbnails) = 0;
+                                 Images>* thumbnails) = 0;
 
   // Set a thumbnail for a URL. |url_rank| is the position of the URL
   // in the list of TopURLs, zero-based.
@@ -46,20 +45,20 @@ class TopSitesDatabase {
   // thumbnail.
   virtual void SetPageThumbnail(const MostVisitedURL& url,
                                 int url_rank,
-                                const TopSites::Images& thumbnail) = 0;
+                                const 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,
-                        TopSites::Images* thumbnail) {
+                        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,
-                                TopSites::Images* thumbnail) = 0;
+                                Images* thumbnail) = 0;
 
   // Remove the record for this URL. Returns true iff removed successfully.
   virtual bool RemoveURL(const MostVisitedURL& url) = 0;
@@ -79,7 +78,7 @@ 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, TopSites::Images>* thumbnails);
+                                 std::map<GURL, Images>* thumbnails);
 
   // Set a thumbnail for a URL. |url_rank| is the position of the URL
   // in the list of TopURLs, zero-based.
@@ -87,7 +86,7 @@ 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 TopSites::Images& thumbnail);
+                                const Images& thumbnail);
 
   // Sets the rank for a given URL. The URL must be in the database.
   // Use SetPageThumbnail if it's not.
@@ -95,7 +94,7 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   virtual bool GetPageThumbnail(const GURL& url,
-                                TopSites::Images* thumbnail);
+                                Images* thumbnail);
 
   // Remove the record for this URL. Returns true iff removed successfully.
   virtual bool RemoveURL(const MostVisitedURL& url);
@@ -108,14 +107,14 @@ class TopSitesDatabaseImpl : public TopSitesDatabase {
   // Adds a new URL to the database.
   void AddPageThumbnail(const MostVisitedURL& url,
                         int new_rank,
-                        const TopSites::Images& thumbnail);
+                        const 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 TopSites::Images& thumbnail);
+                           const 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 b685319..d06f671 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();
-    top_sites_ = NULL;
+    TopSites::DeleteTopSites(top_sites_);
     EXPECT_TRUE(file_util::Delete(file_name_, false));
   }
 
@@ -92,7 +92,6 @@ 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);
   }
 
@@ -105,6 +104,10 @@ 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_;
@@ -121,6 +124,7 @@ 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:
@@ -188,14 +192,14 @@ class MockHistoryServiceImpl : public TopSites::MockHistoryService {
 class MockTopSitesDatabaseImpl : public TopSitesDatabase {
  public:
   virtual void GetPageThumbnails(MostVisitedURLList* urls,
-                                 std::map<GURL, TopSites::Images>* thumbnails) {
+                                 std::map<GURL, 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 TopSites::Images& thumbnail) {
+                                const Images& thumbnail) {
     SetPageRank(url, url_rank);
     // Update thubmnail
     thumbnails_map_[url.url] = thumbnail;
@@ -229,8 +233,8 @@ class MockTopSitesDatabaseImpl : public TopSitesDatabase {
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   virtual bool GetPageThumbnail(const GURL& url,
-                                TopSites::Images* thumbnail) {
-    std::map<GURL, TopSites::Images>::const_iterator found =
+                                Images* thumbnail) {
+    std::map<GURL, Images>::const_iterator found =
         thumbnails_map_.find(url);
     if (found == thumbnails_map_.end())
       return false;  // No thumbnail for this URL.
@@ -255,7 +259,7 @@ class MockTopSitesDatabaseImpl : public TopSitesDatabase {
 
  private:
   MostVisitedURLList top_sites_list_;  // Keeps the URLs sorted by score (rank).
-  std::map<GURL, TopSites::Images> thumbnails_map_;
+  std::map<GURL, Images> thumbnails_map_;
 };
 
 
@@ -448,7 +452,7 @@ TEST_F(TopSitesTest, MockDatabase) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  TopSites::Images thumbnail;
+  Images thumbnail;
   db->SetPageThumbnail(url, 0, thumbnail);
 
   top_sites().ReadDatabase();
@@ -495,7 +499,7 @@ TEST_F(TopSitesTest, MockDatabase) {
   top_sites().StartQueryForMostVisited();
   MessageLoop::current()->RunAllPending();
 
-  std::map<GURL, TopSites::Images> thumbnails;
+  std::map<GURL, Images> thumbnails;
   MostVisitedURLList result;
   db->GetPageThumbnails(&result, &thumbnails);
   ASSERT_EQ(4u, result.size());
@@ -520,18 +524,18 @@ TEST_F(TopSitesTest, TopSitesDB) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  TopSites::Images thumbnail;
+  Images thumbnail;
   thumbnail.thumbnail = random_thumbnail();
   // Add asdf at rank 0.
   db.SetPageThumbnail(url, 0, thumbnail);
 
-  TopSites::Images result;
+  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, TopSites::Images> thumbnails;
+  std::map<GURL, Images> thumbnails;
   db.GetPageThumbnails(&urls, &thumbnails);
   ASSERT_EQ(1u, urls.size());
   EXPECT_EQ(asdf_url, urls[0].url);
@@ -607,7 +611,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   url.url = asdf_url;
   url.title = asdf_title;
   url.redirects.push_back(url.url);
-  TopSites::Images thumbnail;
+  Images thumbnail;
   thumbnail.thumbnail = random_thumbnail();
   db->SetPageThumbnail(url, 0, thumbnail);
 
@@ -623,7 +627,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   EXPECT_EQ(welcome_url(), urls()[1].url);
   EXPECT_EQ(themes_url(), urls()[2].url);
 
-  TopSites::Images img_result;
+  Images img_result;
   db->GetPageThumbnail(asdf_url, &img_result);
   EXPECT_TRUE(img_result.thumbnail != NULL);
   EXPECT_TRUE(ThumbnailsAreEqual(random_thumbnail(), img_result.thumbnail));
@@ -641,7 +645,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   url2.redirects.push_back(google3_url);
 
   // Add new thumbnail at rank 0 and shift the other result to 1.
-  TopSites::Images g_thumbnail;
+  Images g_thumbnail;
   g_thumbnail.thumbnail = google_thumbnail();
   db->SetPageThumbnail(url2, 0, g_thumbnail);
 
@@ -676,7 +680,7 @@ TEST_F(TopSitesTest, RealDatabase) {
   top_sites().StartQueryForMostVisited();
   MessageLoop::current()->RunAllPending();
 
-  std::map<GURL, TopSites::Images> thumbnails;
+  std::map<GURL, Images> thumbnails;
   MostVisitedURLList results;
   db->GetPageThumbnails(&results, &thumbnails);
   ASSERT_EQ(4u, results.size());
@@ -697,7 +701,7 @@ TEST_F(TopSitesTest, RealDatabase) {
                                            *weewar_bitmap,
                                            medium_score));
   RefCountedBytes* out_1;
-  TopSites::Images out_2;
+  Images out_2;
   EXPECT_TRUE(top_sites().GetPageThumbnail(google1_url, &out_1));
 
   MessageLoop::current()->RunAllPending();
@@ -1074,7 +1078,11 @@ TEST_F(TopSitesTest, Blacklisting) {
                   &TopSitesTest::OnTopSitesAvailable));
   top_sites().OnTopSitesAvailable(0, pages);
   MessageLoop::current()->RunAllPending();
-  EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
+  {
+    Lock& l = lock();
+    AutoLock lock(l);  // IsBlacklisted must be in a lock.
+    EXPECT_FALSE(top_sites().IsBlacklisted(GURL("http://bbc.com/")));
+  }
 
   EXPECT_EQ(1u, number_of_callbacks());
 
@@ -1085,9 +1093,13 @@ TEST_F(TopSitesTest, Blacklisting) {
   EXPECT_EQ(themes_url(), urls()[3].url);
 
   top_sites().AddBlacklistedURL(GURL("http://google.com/"));
-  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()));
+  {
+    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()));
+  }
 
   top_sites().GetMostVisitedURLs(
       &c,
@@ -1110,7 +1122,11 @@ TEST_F(TopSitesTest, Blacklisting) {
   EXPECT_EQ(themes_url(), urls()[1].url);
 
   top_sites().RemoveBlacklistedURL(GURL("http://google.com/"));
-  EXPECT_FALSE(top_sites().IsBlacklisted(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/")));
+  }
 
   top_sites().GetMostVisitedURLs(
       &c,
@@ -1151,7 +1167,6 @@ 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());
@@ -1161,9 +1176,6 @@ 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 bb335bf..63269b2 100644
--- a/chrome/browser/profile_impl.cc
+++ b/chrome/browser/profile_impl.cc
@@ -465,6 +465,9 @@ ProfileImpl::~ProfileImpl() {
   if (web_data_service_.get())
     web_data_service_->Shutdown();
 
+  if (top_sites_.get())
+    top_sites_->ClearProfile();
+
   if (history_service_.get())
     history_service_->Cleanup();
 
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 96c2411..3e43c8f 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -2485,7 +2485,7 @@ void TabContents::UpdateThumbnail(const GURL& url,
                                   const SkBitmap& bitmap,
                                   const ThumbnailScore& score) {
   // Tell History about this thumbnail
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kTopSites)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kNoTopSites)) {
     if (!profile()->IsOffTheRecord())
       profile()->GetTopSites()->SetPageThumbnail(url, bitmap, score);
   } else {