Remove adapter method on HistoryBackend delegating to AndroidProviderBackend

chrome/browser/history/android/android_history_provider_service.cc

Index: chrome/browser/history/android/android_history_provider_service.cc
diff --git a/chrome/browser/history/android/android_history_provider_service.cc b/chrome/browser/history/android/android_history_provider_service.cc
index 149fa5b3540ab89678209b8a657dec67e0838a4d..4f3e8289631e3c1ca334a7a74f34a1004b914368 100644
--- a/chrome/browser/history/android/android_history_provider_service.cc
+++ b/chrome/browser/history/android/android_history_provider_service.cc
@@ -6,12 +6,236 @@
 
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
+#include "chrome/browser/history/android/android_provider_backend.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/profiles/profile.h"
+#include "components/history/core/browser/android/android_history_types.h"
+#include "components/history/core/browser/history_db_task.h"
 
-using history::HistoryBackend;
+namespace {
+
+// AndroidProviderTask wraps two callbacks into an HistoryDBTask so that they
+// can be passed to HistoryService::ScheduleDBTask. ResultType must be zero
+// constructible (i.e. ResultType(0) should build an initialized default value)
+// and copyable.
+template <typename ResultType>
+class AndroidProviderTask : public history::HistoryDBTask {
+ public:
+  typedef base::Callback<ResultType(history::AndroidProviderBackend*)>
+      RequestCallback;
+  typedef base::Callback<void(ResultType)> ResultCallback;
+
+  AndroidProviderTask(const RequestCallback& request_cb,
+                      const ResultCallback& result_cb)
+      : request_cb_(request_cb), result_cb_(result_cb), result_(0) {
+    DCHECK(!request_cb_.is_null());
+    DCHECK(!result_cb_.is_null());
+  }
+
+  ~AndroidProviderTask() override {}
+
+ private:
+  // history::HistoryDBTask implementation.
+  bool RunOnDBThread(history::HistoryBackend* backend,
+                     history::HistoryDatabase* db) override {
+    if (backend->android_provider_backend())
+      result_ = request_cb_.Run(backend->android_provider_backend());
+    return true;
+  }
+
+  void DoneRunOnMainThread() override { result_cb_.Run(result_); }
+
+  RequestCallback request_cb_;
+  ResultCallback result_cb_;
+  ResultType result_;
+};
+
+// Creates an instance of AndroidProviderTask using the two callback and using
+// type deduction.
+template <typename ResultType>
+scoped_ptr<history::HistoryDBTask> CreateAndroidProviderTask(
+    const base::Callback<ResultType(history::AndroidProviderBackend*)>&
+        request_cb,
+    const base::Callback<void(ResultType)>& result_cb) {
+  return scoped_ptr<history::HistoryDBTask>(
+      new AndroidProviderTask<ResultType>(request_cb, result_cb));
+}
+
+// History and bookmarks ----------------------------------------------------
+
+// Inserts the given values into android provider backend.
+history::AndroidURLID InsertHistoryAndBookmarkAdapter(
+    const history::HistoryAndBookmarkRow& row,
+    history::AndroidProviderBackend* backend) {
+  return backend->InsertHistoryAndBookmark(row);
+}
+
+// Runs the given query on android provider backend and returns the result.
+//
+// |projections| is the vector of the result columns.
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for WHERE clause.
+// |sort_order| is the SQL ORDER clause.
+history::AndroidStatement* QueryHistoryAndBookmarksAdapter(
+    const std::vector<history::HistoryAndBookmarkRow::ColumnID>& projections,
+    const std::string& selection,
+    const std::vector<base::string16>& selection_args,
+    const std::string& sort_order,
+    history::AndroidProviderBackend* backend) {
+  return backend->QueryHistoryAndBookmarks(projections, selection,
+                                           selection_args, sort_order);
+}
+
+// Returns the number of row updated by the update query.
+//
+// |row| is the value to update.
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for the WHERE clause.
+int UpdateHistoryAndBookmarksAdapter(
+    const history::HistoryAndBookmarkRow& row,
+    const std::string& selection,
+    const std::vector<base::string16>& selection_args,
+    history::AndroidProviderBackend* backend) {
+  int count = 0;
+  backend->UpdateHistoryAndBookmarks(row, selection, selection_args, &count);
+  return count;
+}
+
+// Deletes the specified rows and returns the number of rows deleted.
+//
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for the WHERE clause.
+//
+// If |selection| is empty all history and bookmarks are deleted.
+int DeleteHistoryAndBookmarksAdapter(
+    const std::string& selection,
+    const std::vector<base::string16>& selection_args,
+    history::AndroidProviderBackend* backend) {
+  int count = 0;
+  backend->DeleteHistoryAndBookmarks(selection, selection_args, &count);
+  return count;
+}
+
+// Deletes the matched history and returns the number of rows deleted.
+int DeleteHistoryAdapter(const std::string& selection,
+                         const std::vector<base::string16>& selection_args,
+                         history::AndroidProviderBackend* backend) {
+  int count = 0;
+  backend->DeleteHistory(selection, selection_args, &count);
+  return count;
+}
+
+// Statement ----------------------------------------------------------------
+
+// Move the statement's current position.
+int MoveStatementAdapter(history::AndroidStatement* statement,
+                         int current_pos,
+                         int destination,
+                         history::AndroidProviderBackend* backend) {
+  DCHECK_LE(-1, current_pos);
+  DCHECK_LE(-1, destination);
+
+  int cur = current_pos;
+  if (current_pos > destination) {
+    statement->statement()->Reset(false);
+    cur = -1;
+  }
+  for (; cur < destination; ++cur) {
+    if (!statement->statement()->Step())
+      break;
+  }
+
+  return cur;
+}
+
+// CloseStatementTask delete the passed |statement| in the DB thread (or in the
+// UI thread if the HistoryBackend is destroyed before the task is executed).
+class CloseStatementTask : public history::HistoryDBTask {
+ public:
+  // Close the given statement. The ownership is transfered.
+  explicit CloseStatementTask(history::AndroidStatement* statement)
+      : statement_(statement) {
+    DCHECK(statement_);
+  }
+
+  ~CloseStatementTask() override { delete statement_; }
+
+  // Returns the cancelable task tracker to use for this task. The task owns it,
+  // so it can never be cancelled. This is required due to be compatible with
+  // HistoryService::ScheduleDBTask() interface.
+  base::CancelableTaskTracker* tracker() { return &tracker_; }
+
+ private:
+  // history::HistoryDBTask implementation.
+  bool RunOnDBThread(history::HistoryBackend* backend,
+                     history::HistoryDatabase* db) override {
+    delete statement_;
+    statement_ = nullptr;
+    return true;
+  }
+
+  void DoneRunOnMainThread() override {}
+
+  history::AndroidStatement* statement_;
+  base::CancelableTaskTracker tracker_;
+};
+
+// Search terms -------------------------------------------------------------
+
+// Inserts the given values and returns the SearchTermID of the inserted row.
+history::SearchTermID InsertSearchTermAdapter(
+    const history::SearchRow& row,
+    history::AndroidProviderBackend* backend) {
+  return backend->InsertSearchTerm(row);
+}
+
+// Returns the number of row updated by the update query.
+//
+// |row| is the value to update.
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for the WHERE clause.
+int UpdateSearchTermsAdapter(const history::SearchRow& row,
+                             const std::string& selection,
+                             const std::vector<base::string16> selection_args,
+                             history::AndroidProviderBackend* backend) {
+  int count = 0;
+  backend->UpdateSearchTerms(row, selection, selection_args, &count);
+  return count;
+}
+
+// Deletes the matched rows and returns the number of deleted rows.
+//
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for WHERE clause.
+//
+// If |selection| is empty all search terms will be deleted.
+int DeleteSearchTermsAdapter(const std::string& selection,
+                             const std::vector<base::string16> selection_args,
+                             history::AndroidProviderBackend* backend) {
+  int count = 0;
+  backend->DeleteSearchTerms(selection, selection_args, &count);
+  return count;
+}
+
+// Returns the result of the given query.
+//
+// |projections| specifies the result columns.
+// |selection| is the SQL WHERE clause without 'WHERE'.
+// |selection_args| is the arguments for WHERE clause.
+// |sort_order| is the SQL ORDER clause.
+history::AndroidStatement* QuerySearchTermsAdapter(
+    const std::vector<history::SearchRow::ColumnID>& projections,
+    const std::string& selection,
+    const std::vector<base::string16>& selection_args,
+    const std::string& sort_order,
+    history::AndroidProviderBackend* backend) {
+  return backend->QuerySearchTerms(projections, selection, selection_args,
+                                   sort_order);
+}
+
+}  // namespace
 
 AndroidHistoryProviderService::AndroidHistoryProviderService(Profile* profile)
     : profile_(profile) {
@@ -30,23 +254,16 @@ AndroidHistoryProviderService::QueryHistoryAndBookmarks(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::QueryHistoryAndBookmarks,
-                   hs->history_backend_.get(),
-                   projections,
-                   selection,
-                   selection_args,
-                   sort_order),
-        callback);
-  } else {
-    callback.Run(NULL);
+  if (!hs) {
+    callback.Run(nullptr);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&QueryHistoryAndBookmarksAdapter, projections, selection,
+                     selection_args, sort_order),
+          callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -58,22 +275,15 @@ AndroidHistoryProviderService::UpdateHistoryAndBookmarks(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::UpdateHistoryAndBookmarks,
-                   hs->history_backend_.get(),
-                   row,
-                   selection,
-                   selection_args),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(base::Bind(&UpdateHistoryAndBookmarksAdapter,
+                                           row, selection, selection_args),
+                                callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -84,21 +294,15 @@ AndroidHistoryProviderService::DeleteHistoryAndBookmarks(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::DeleteHistoryAndBookmarks,
-                   hs->history_backend_.get(),
-                   selection,
-                   selection_args),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(base::Bind(&DeleteHistoryAndBookmarksAdapter,
+                                           selection, selection_args),
+                                callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -108,20 +312,14 @@ AndroidHistoryProviderService::InsertHistoryAndBookmark(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::InsertHistoryAndBookmark,
-                   hs->history_backend_.get(),
-                   values),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&InsertHistoryAndBookmarkAdapter, values), callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -132,21 +330,15 @@ AndroidHistoryProviderService::DeleteHistory(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::DeleteHistory,
-                   hs->history_backend_.get(),
-                   selection,
-                   selection_args),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&DeleteHistoryAdapter, selection, selection_args),
+          callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -158,35 +350,28 @@ AndroidHistoryProviderService::MoveStatement(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::MoveStatement,
-                   hs->history_backend_.get(),
-                   statement,
-                   current_pos,
-                   destination),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(current_pos);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(base::Bind(&MoveStatementAdapter, statement,
+                                           current_pos, destination),
+                                callback),
+      tracker);
 }
 
 void AndroidHistoryProviderService::CloseStatement(
     history::AndroidStatement* statement) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    hs->ScheduleTask(HistoryService::PRIORITY_NORMAL,
-                     base::Bind(&HistoryBackend::CloseStatement,
-                                hs->history_backend_.get(), statement));
-  } else {
+  if (!hs) {
     delete statement;
+    return;
   }
+  scoped_ptr<CloseStatementTask> task(new CloseStatementTask(statement));
+  base::CancelableTaskTracker* tracker = task->tracker();
+  hs->ScheduleDBTask(task.Pass(), tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -196,19 +381,14 @@ AndroidHistoryProviderService::InsertSearchTerm(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(
-            &HistoryBackend::InsertSearchTerm, hs->history_backend_.get(), row),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(base::Bind(&InsertSearchTermAdapter, row),
+                                callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -220,22 +400,15 @@ AndroidHistoryProviderService::UpdateSearchTerms(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::UpdateSearchTerms,
-                   hs->history_backend_.get(),
-                   row,
-                   selection,
-                   selection_args),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&UpdateSearchTermsAdapter, row, selection, selection_args),
+          callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -246,21 +419,15 @@ AndroidHistoryProviderService::DeleteSearchTerms(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::DeleteSearchTerms,
-                   hs->history_backend_.get(),
-                   selection,
-                   selection_args),
-        callback);
-  } else {
+  if (!hs) {
     callback.Run(0);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&DeleteSearchTermsAdapter, selection, selection_args),
+          callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId
@@ -273,23 +440,16 @@ AndroidHistoryProviderService::QuerySearchTerms(
     base::CancelableTaskTracker* tracker) {
   HistoryService* hs = HistoryServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  if (hs) {
-    DCHECK(hs->thread_) << "History service being called after cleanup";
-    DCHECK(hs->thread_checker_.CalledOnValidThread());
-    return tracker->PostTaskAndReplyWithResult(
-        hs->thread_->message_loop_proxy().get(),
-        FROM_HERE,
-        base::Bind(&HistoryBackend::QuerySearchTerms,
-                   hs->history_backend_.get(),
-                   projections,
-                   selection,
-                   selection_args,
-                   sort_order),
-        callback);
-  } else {
-    callback.Run(NULL);
+  if (!hs) {
+    callback.Run(nullptr);
     return base::CancelableTaskTracker::kBadTaskId;
   }
+  return hs->ScheduleDBTask(
+      CreateAndroidProviderTask(
+          base::Bind(&QuerySearchTermsAdapter, projections, selection,
+                     selection_args, sort_order),
+          callback),
+      tracker);
 }
 
 base::CancelableTaskTracker::TaskId