Recreate the WebData database on a catastrophic SQL error

components/webdata/common/web_database_backend.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/webdata/common/web_database_backend.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 41 matching lines @@
     db_->AddTable(table);
 
   // Unretained to avoid a ref loop since we own |db_|.
   db_->set_error_callback(base::Bind(&WebDatabaseBackend::DatabaseErrorCallback,
                                      base::Unretained(this)));
   diagnostics_.clear();
   init_status_ = db_->Init(db_path_);
   if (init_status_ != sql::INIT_OK) {
     LOG(ERROR) << "Cannot initialize the web database: " << init_status_;
     diagnostics_ += sql::GetCorruptFileDiagnosticsInfo(db_path_);
-    db_.reset();
+    if (!catastrophic_error_occurred_)
+      db_.reset();
     return init_status_;
   }
 
   db_->BeginTransaction();
   return init_status_;
 }
 
 void WebDatabaseBackend::ShutdownDatabase() {
   if (db_ && init_status_ == sql::INIT_OK)
     db_->CommitTransaction();
@@ skipping 44 matching lines @@
 WebDatabaseBackend::~WebDatabaseBackend() {
   ShutdownDatabase();
 }
 
 void WebDatabaseBackend::DatabaseErrorCallback(int error,
                                                sql::Statement* statement) {
   // We ignore any further error callbacks after the first catastrophic error.
   if (!catastrophic_error_occurred_ && sql::IsErrorCatastrophic(error)) {
     catastrophic_error_occurred_ = true;
     diagnostics_ = db_->GetDiagnosticInfo(error, statement);
+
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&WebDatabaseBackend::RazeAndCloseDatabase, this));
   }
 }
 
+void WebDatabaseBackend::RazeAndCloseDatabase() {
+  if (!db_)
+    return;
+
+  db_->GetSQLConnection()->RollbackAllTransactions();
+  db_->GetSQLConnection()->Raze();
+  db_.reset();

[Scott Hess - ex-Googler, 2016/08/10 17:16:19]

These three lines are essentially identical to what
sql::Connection::RazeAndClose() does.  Additionally, RazeAndClose() is intended
to work correctly when called from within the error callback, so using that
would mean you don't have to post a task and carry around a database handle you
know to reference a potentially-corrupt database.

[afakhry, 2016/08/11 17:32:54]

Interesting. Thanks! Done.

+}
+
 void WebDatabaseBackend::Commit() {
   DCHECK(db_);
   DCHECK_EQ(sql::INIT_OK, init_status_);
   db_->CommitTransaction();
   db_->BeginTransaction();
 }