[IndexedDB] Closing mojo connections when renderer quits

content/browser/indexed_db/indexed_db_callbacks.cc

 // Copyright (c) 2012 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 "content/browser/indexed_db/indexed_db_callbacks.h"
 
 #include <stddef.h>
 
 #include <algorithm>
+#include <memory>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/sequenced_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/fileapi/fileapi_message_filter.h"
 #include "content/browser/indexed_db/cursor_impl.h"
 #include "content/browser/indexed_db/database_impl.h"
 #include "content/browser/indexed_db/indexed_db_connection.h"
 #include "content/browser/indexed_db/indexed_db_context_impl.h"
 #include "content/browser/indexed_db/indexed_db_cursor.h"
 #include "content/browser/indexed_db/indexed_db_database_error.h"
 #include "content/browser/indexed_db/indexed_db_return_value.h"
 #include "content/browser/indexed_db/indexed_db_tracing.h"
 #include "content/browser/indexed_db/indexed_db_transaction.h"
 #include "content/browser/indexed_db/indexed_db_value.h"
 #include "content/common/indexed_db/indexed_db_constants.h"
 #include "content/common/indexed_db/indexed_db_metadata.h"
+#include "content/public/browser/browser_thread.h"
 #include "mojo/public/cpp/bindings/strong_associated_binding.h"
 #include "storage/browser/blob/blob_storage_context.h"
 #include "storage/browser/blob/shareable_file_reference.h"
 #include "storage/browser/quota/quota_manager.h"
 
 using indexed_db::mojom::CallbacksAssociatedPtrInfo;
 using std::swap;
 using storage::ShareableFileReference;
 
 namespace content {
 
 namespace {
 
+// If this is destructed with the connection still living inside it, we assume
+// we have been killed due to IO thread shutdown, and we need to safely schedule
+// the destruction of the connection on the IDB thread, as we should still be in
+// a transaction's operation queue, where we cannot destroy the transaction.
+struct SafeIOThreadConnectionWrapper {
+  SafeIOThreadConnectionWrapper(std::unique_ptr<IndexedDBConnection> connection)
+      : connection(std::move(connection)),
+        idb_runner(base::ThreadTaskRunnerHandle::Get()) {}
+  ~SafeIOThreadConnectionWrapper() {
+    if (connection) {
+      idb_runner->PostTask(
+          FROM_HERE, base::Bind(
+                         [](std::unique_ptr<IndexedDBConnection> connection) {
+                           connection->ForceClose();
+                         },
+                         base::Passed(&connection)));
+    }
+  }
+  SafeIOThreadConnectionWrapper(SafeIOThreadConnectionWrapper&& other) =
+      default;
+
+  std::unique_ptr<IndexedDBConnection> connection;
+  scoped_refptr<base::SequencedTaskRunner> idb_runner;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SafeIOThreadConnectionWrapper);
+};
+
 void ConvertBlobInfo(
     const std::vector<IndexedDBBlobInfo>& blob_info,
     std::vector<::indexed_db::mojom::BlobInfoPtr>* blob_or_file_info) {
   blob_or_file_info->reserve(blob_info.size());
   for (const auto& iter : blob_info) {
     if (!iter.mark_used_callback().is_null())
       iter.mark_used_callback().Run();
 
     auto info = ::indexed_db::mojom::BlobInfo::New();
     info->mime_type = iter.type();
@@ skipping 21 matching lines @@
     swap(mojo_value->value->bits, value->bits);
   ConvertBlobInfo(value->blob_info, &mojo_value->value->blob_or_file_info);
   return mojo_value;
 }
 
 }  // namespace
 
 class IndexedDBCallbacks::IOThreadHelper {
  public:
   IOThreadHelper(CallbacksAssociatedPtrInfo callbacks_info,
-                 scoped_refptr<IndexedDBDispatcherHost> dispatcher_host);
+                 base::WeakPtr<IndexedDBDispatcherHost> dispatcher_host,
+                 url::Origin origin,
+                 scoped_refptr<base::SequencedTaskRunner> idb_runner);
   ~IOThreadHelper();
 
   void SendError(const IndexedDBDatabaseError& error);
   void SendSuccessStringList(const std::vector<base::string16>& value);
   void SendBlocked(int64_t existing_version);
-  void SendUpgradeNeeded(std::unique_ptr<DatabaseImpl> database,
+  void SendUpgradeNeeded(SafeIOThreadConnectionWrapper connection,
                          int64_t old_version,
                          blink::WebIDBDataLoss data_loss,
                          const std::string& data_loss_message,
                          const content::IndexedDBDatabaseMetadata& metadata);
-  void SendSuccessDatabase(std::unique_ptr<DatabaseImpl> database,
+  void SendSuccessDatabase(SafeIOThreadConnectionWrapper connection,
                            const content::IndexedDBDatabaseMetadata& metadata);
-  void SendSuccessCursor(std::unique_ptr<CursorImpl> cursor,
+  void SendSuccessCursor(std::unique_ptr<IndexedDBCursor> cursor,
                          const IndexedDBKey& key,
                          const IndexedDBKey& primary_key,
                          ::indexed_db::mojom::ValuePtr value,
                          const std::vector<IndexedDBBlobInfo>& blob_info);
   void SendSuccessValue(::indexed_db::mojom::ReturnValuePtr value,
                         const std::vector<IndexedDBBlobInfo>& blob_info);
   void SendSuccessCursorContinue(
       const IndexedDBKey& key,
       const IndexedDBKey& primary_key,
       ::indexed_db::mojom::ValuePtr value,
@@ skipping 10 matching lines @@
   void SendSuccessInteger(int64_t value);
   void SendSuccess();
 
   std::string CreateBlobData(const IndexedDBBlobInfo& blob_info);
   bool CreateAllBlobs(
       const std::vector<IndexedDBBlobInfo>& blob_info,
       std::vector<::indexed_db::mojom::BlobInfoPtr>* blob_or_file_info);
   void OnConnectionError();
 
  private:
-  scoped_refptr<IndexedDBDispatcherHost> dispatcher_host_;
+  base::WeakPtr<IndexedDBDispatcherHost> dispatcher_host_;
   ::indexed_db::mojom::CallbacksAssociatedPtr callbacks_;
+  url::Origin origin_;
+  scoped_refptr<base::SequencedTaskRunner> idb_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThreadHelper);
 };
 
 // static
 ::indexed_db::mojom::ValuePtr IndexedDBCallbacks::ConvertAndEraseValue(
     IndexedDBValue* value) {
   auto mojo_value = ::indexed_db::mojom::Value::New();
   if (!value->empty())
     swap(mojo_value->bits, value->bits);
   ConvertBlobInfo(value->blob_info, &mojo_value->blob_or_file_info);
   return mojo_value;
 }
 
 IndexedDBCallbacks::IndexedDBCallbacks(
-    scoped_refptr<IndexedDBDispatcherHost> dispatcher_host,
+    base::WeakPtr<IndexedDBDispatcherHost> dispatcher_host,
     const url::Origin& origin,
-    ::indexed_db::mojom::CallbacksAssociatedPtrInfo callbacks_info)
-    : dispatcher_host_(std::move(dispatcher_host)),
-      origin_(origin),
-      data_loss_(blink::kWebIDBDataLossNone),
-      sent_blocked_(false),
-      io_helper_(
-          new IOThreadHelper(std::move(callbacks_info), dispatcher_host_)) {
+    ::indexed_db::mojom::CallbacksAssociatedPtrInfo callbacks_info,
+    scoped_refptr<base::SequencedTaskRunner> idb_runner)
+    : data_loss_(blink::kWebIDBDataLossNone),
+      io_helper_(new IOThreadHelper(std::move(callbacks_info),
+                                    std::move(dispatcher_host),
+                                    origin,
+                                    std::move(idb_runner))) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   thread_checker_.DetachFromThread();
 }
 
 IndexedDBCallbacks::~IndexedDBCallbacks() {
   DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 void IndexedDBCallbacks::OnError(const IndexedDBDatabaseError& error) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendError, base::Unretained(io_helper_.get()),
                  error));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 
   if (!connection_open_start_time_.is_null()) {
     UMA_HISTOGRAM_MEDIUM_TIMES(
         "WebCore.IndexedDB.OpenTime.Error",
         base::TimeTicks::Now() - connection_open_start_time_);
     connection_open_start_time_ = base::TimeTicks();
   }
 }
 
 void IndexedDBCallbacks::OnSuccess(const std::vector<base::string16>& value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessStringList,
                  base::Unretained(io_helper_.get()), value));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnBlocked(int64_t existing_version) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   if (sent_blocked_)
     return;
 
   sent_blocked_ = true;
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendBlocked,
                  base::Unretained(io_helper_.get()), existing_version));
 
   if (!connection_open_start_time_.is_null()) {
     UMA_HISTOGRAM_MEDIUM_TIMES(
         "WebCore.IndexedDB.OpenTime.Blocked",
         base::TimeTicks::Now() - connection_open_start_time_);
     connection_open_start_time_ = base::TimeTicks();
   }
 }
 
 void IndexedDBCallbacks::OnUpgradeNeeded(
     int64_t old_version,
     std::unique_ptr<IndexedDBConnection> connection,
     const IndexedDBDatabaseMetadata& metadata,
     const IndexedDBDataLossInfo& data_loss_info) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
-  DCHECK(!database_sent_);
+  DCHECK(!database_created_);

[jsbell, 2017/04/11 16:58:04]

This should really refer to 'connection' not 'database'; it ends up being an
IDBDatabase instance on the blink side but it's really a connection. 

(I suppose we call the mojo interface for it 'database', though...)

[dmurph, 2017/04/11 19:32:49]

Done.

 
   data_loss_ = data_loss_info.status;
-  database_sent_ = true;
-  auto database = base::MakeUnique<DatabaseImpl>(std::move(connection), origin_,
-                                                 dispatcher_host_);
+  database_created_ = true;
 
+  SafeIOThreadConnectionWrapper wrapper(std::move(connection));
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendUpgradeNeeded,
-                 base::Unretained(io_helper_.get()), base::Passed(&database),
+                 base::Unretained(io_helper_.get()), base::Passed(&wrapper),
                  old_version, data_loss_info.status, data_loss_info.message,
                  metadata));
 
   if (!connection_open_start_time_.is_null()) {
     UMA_HISTOGRAM_MEDIUM_TIMES(
         "WebCore.IndexedDB.OpenTime.UpgradeNeeded",
         base::TimeTicks::Now() - connection_open_start_time_);
     connection_open_start_time_ = base::TimeTicks();
   }
 }
 
 void IndexedDBCallbacks::OnSuccess(
     std::unique_ptr<IndexedDBConnection> connection,
     const IndexedDBDatabaseMetadata& metadata) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
-  DCHECK_EQ(database_sent_, !connection);
+  DCHECK_EQ(database_created_, !connection);
 
   scoped_refptr<IndexedDBCallbacks> self(this);
 
-  // Only send a new Database if the connection was not previously sent in
+  // Only create a new connection if the database was not previously sent in

[jsbell, 2017/04/11 16:58:03]

s/database/one/

[dmurph, 2017/04/11 19:32:49]

Done.

   // OnUpgradeNeeded.
-  std::unique_ptr<DatabaseImpl> database;
-  if (!database_sent_) {
-    database.reset(
-        new DatabaseImpl(std::move(connection), origin_, dispatcher_host_));
-  }
+  std::unique_ptr<IndexedDBConnection> database_connection;
+  if (!database_created_)
+    database_connection = std::move(connection);
 
+  SafeIOThreadConnectionWrapper wrapper(std::move(database_connection));
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                           base::Bind(&IOThreadHelper::SendSuccessDatabase,
                                      base::Unretained(io_helper_.get()),
-                                     base::Passed(&database), metadata));
-  dispatcher_host_ = nullptr;
+                                     base::Passed(&wrapper), metadata));
+  closed_ = true;

[jsbell, 2017/04/11 16:58:04]

Seeing this usage, maybe rename 'complete_' or 'done_' ?

"closed" sounds too much like "connection closed"

[dmurph, 2017/04/11 19:32:49]

Done.

 
   if (!connection_open_start_time_.is_null()) {
     UMA_HISTOGRAM_MEDIUM_TIMES(
         "WebCore.IndexedDB.OpenTime.Success",
         base::TimeTicks::Now() - connection_open_start_time_);
     connection_open_start_time_ = base::TimeTicks();
   }
 }
 
 void IndexedDBCallbacks::OnSuccess(std::unique_ptr<IndexedDBCursor> cursor,
                                    const IndexedDBKey& key,
                                    const IndexedDBKey& primary_key,
                                    IndexedDBValue* value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
-  auto cursor_impl = base::MakeUnique<CursorImpl>(std::move(cursor), origin_,
-                                                  dispatcher_host_);
-
   ::indexed_db::mojom::ValuePtr mojo_value;
   std::vector<IndexedDBBlobInfo> blob_info;
   if (value) {
     mojo_value = ConvertAndEraseValue(value);
     blob_info.swap(value->blob_info);
   }
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessCursor,
-                 base::Unretained(io_helper_.get()), base::Passed(&cursor_impl),
-                 key, primary_key, base::Passed(&mojo_value),
+                 base::Unretained(io_helper_.get()), base::Passed(&cursor), key,
+                 primary_key, base::Passed(&mojo_value),
                  base::Passed(&blob_info)));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccess(const IndexedDBKey& key,
                                    const IndexedDBKey& primary_key,
                                    IndexedDBValue* value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   ::indexed_db::mojom::ValuePtr mojo_value;
   std::vector<IndexedDBBlobInfo> blob_info;
   if (value) {
     mojo_value = ConvertAndEraseValue(value);
     blob_info.swap(value->blob_info);
   }
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessCursorContinue,
                  base::Unretained(io_helper_.get()), key, primary_key,
                  base::Passed(&mojo_value), base::Passed(&blob_info)));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccessWithPrefetch(
     const std::vector<IndexedDBKey>& keys,
     const std::vector<IndexedDBKey>& primary_keys,
     std::vector<IndexedDBValue>* values) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
   DCHECK_EQ(keys.size(), primary_keys.size());
   DCHECK_EQ(keys.size(), values->size());
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   std::vector<::indexed_db::mojom::ValuePtr> mojo_values;
   mojo_values.reserve(values->size());
   for (size_t i = 0; i < values->size(); ++i)
     mojo_values.push_back(ConvertAndEraseValue(&(*values)[i]));
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessCursorPrefetch,
                  base::Unretained(io_helper_.get()), keys, primary_keys,
                  base::Passed(&mojo_values), *values));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccess(IndexedDBReturnValue* value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   ::indexed_db::mojom::ReturnValuePtr mojo_value;
   std::vector<IndexedDBBlobInfo> blob_info;
   if (value) {
     mojo_value = ConvertReturnValue(value);
     blob_info = value->blob_info;
   }
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessValue,
                  base::Unretained(io_helper_.get()), base::Passed(&mojo_value),
                  base::Passed(&blob_info)));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccessArray(
     std::vector<IndexedDBReturnValue>* values) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   std::vector<::indexed_db::mojom::ReturnValuePtr> mojo_values;
   mojo_values.reserve(values->size());
   for (size_t i = 0; i < values->size(); ++i)
     mojo_values.push_back(ConvertReturnValue(&(*values)[i]));
 
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                           base::Bind(&IOThreadHelper::SendSuccessArray,
                                      base::Unretained(io_helper_.get()),
                                      base::Passed(&mojo_values), *values));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccess(const IndexedDBKey& value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessKey,
                  base::Unretained(io_helper_.get()), value));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccess(int64_t value) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&IOThreadHelper::SendSuccessInteger,
                  base::Unretained(io_helper_.get()), value));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::OnSuccess() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(dispatcher_host_);
+  DCHECK(!closed_);
   DCHECK(io_helper_);
 
   DCHECK_EQ(blink::kWebIDBDataLossNone, data_loss_);
 
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                           base::Bind(&IOThreadHelper::SendSuccess,
                                      base::Unretained(io_helper_.get())));
-  dispatcher_host_ = nullptr;
+  closed_ = true;
 }
 
 void IndexedDBCallbacks::SetConnectionOpenStartTime(
     const base::TimeTicks& start_time) {
   connection_open_start_time_ = start_time;
 }
 
 IndexedDBCallbacks::IOThreadHelper::IOThreadHelper(
     CallbacksAssociatedPtrInfo callbacks_info,
-    scoped_refptr<IndexedDBDispatcherHost> dispatcher_host)
-    : dispatcher_host_(std::move(dispatcher_host)) {
+    base::WeakPtr<IndexedDBDispatcherHost> dispatcher_host,
+    url::Origin origin,
+    scoped_refptr<base::SequencedTaskRunner> idb_runner)
+    : dispatcher_host_(std::move(dispatcher_host)),
+      origin_(origin),
+      idb_runner_(idb_runner) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (callbacks_info.is_valid()) {
     callbacks_.Bind(std::move(callbacks_info));
     callbacks_.set_connection_error_handler(
         base::Bind(&IOThreadHelper::OnConnectionError, base::Unretained(this)));
   }
 }
 
 IndexedDBCallbacks::IOThreadHelper::~IOThreadHelper() {}
 
 void IndexedDBCallbacks::IOThreadHelper::SendError(
     const IndexedDBDatabaseError& error) {
-  if (callbacks_)
-    callbacks_->Error(error.code(), error.message());
+  if (!callbacks_)
+    return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  callbacks_->Error(error.code(), error.message());
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessStringList(
     const std::vector<base::string16>& value) {
-  if (callbacks_)
-    callbacks_->SuccessStringList(value);
+  if (!callbacks_)
+    return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  callbacks_->SuccessStringList(value);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendBlocked(int64_t existing_version) {
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
   if (callbacks_)
     callbacks_->Blocked(existing_version);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendUpgradeNeeded(
-    std::unique_ptr<DatabaseImpl> database,
+    SafeIOThreadConnectionWrapper connection_wrapper,
     int64_t old_version,
     blink::WebIDBDataLoss data_loss,
     const std::string& data_loss_message,
     const content::IndexedDBDatabaseMetadata& metadata) {
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+
+  auto database = base::MakeUnique<DatabaseImpl>(
+      std::move(connection_wrapper.connection), origin_, dispatcher_host_.get(),
+      idb_runner_);
 
   ::indexed_db::mojom::DatabaseAssociatedPtrInfo ptr_info;
   auto request = mojo::MakeRequest(&ptr_info);
-  mojo::MakeStrongAssociatedBinding(std::move(database), std::move(request));
+
+  dispatcher_host_->AddDatabaseBinding(std::move(database), std::move(request));
   callbacks_->UpgradeNeeded(std::move(ptr_info), old_version, data_loss,
                             data_loss_message, metadata);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessDatabase(
-    std::unique_ptr<DatabaseImpl> database,
+    SafeIOThreadConnectionWrapper connection_wrapper,
     const content::IndexedDBDatabaseMetadata& metadata) {
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  ::indexed_db::mojom::DatabaseAssociatedPtrInfo ptr_info;
+  if (connection_wrapper.connection) {
+    auto database = base::MakeUnique<DatabaseImpl>(
+        std::move(connection_wrapper.connection), origin_,
+        dispatcher_host_.get(), idb_runner_);
 
-  ::indexed_db::mojom::DatabaseAssociatedPtrInfo ptr_info;
-  if (database) {
     auto request = mojo::MakeRequest(&ptr_info);
-    mojo::MakeStrongAssociatedBinding(std::move(database), std::move(request));
+    dispatcher_host_->AddDatabaseBinding(std::move(database),
+                                         std::move(request));
   }
   callbacks_->SuccessDatabase(std::move(ptr_info), metadata);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessCursor(
-    std::unique_ptr<CursorImpl> cursor,
+    std::unique_ptr<IndexedDBCursor> cursor,
     const IndexedDBKey& key,
     const IndexedDBKey& primary_key,
     ::indexed_db::mojom::ValuePtr value,
     const std::vector<IndexedDBBlobInfo>& blob_info) {
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  auto cursor_impl = base::MakeUnique<CursorImpl>(
+      std::move(cursor), origin_, dispatcher_host_.get(), idb_runner_);
 
   if (value && !CreateAllBlobs(blob_info, &value->blob_or_file_info))
     return;
 
   ::indexed_db::mojom::CursorAssociatedPtrInfo ptr_info;
   auto request = mojo::MakeRequest(&ptr_info);
-  mojo::MakeStrongAssociatedBinding(std::move(cursor), std::move(request));
+  dispatcher_host_->AddCursorBinding(std::move(cursor_impl),
+                                     std::move(request));
   callbacks_->SuccessCursor(std::move(ptr_info), key, primary_key,
                             std::move(value));
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessValue(
     ::indexed_db::mojom::ReturnValuePtr value,
     const std::vector<IndexedDBBlobInfo>& blob_info) {
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
 
   if (!value || CreateAllBlobs(blob_info, &value->value->blob_or_file_info))
     callbacks_->SuccessValue(std::move(value));
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessArray(
     std::vector<::indexed_db::mojom::ReturnValuePtr> mojo_values,
     const std::vector<IndexedDBReturnValue>& values) {
   DCHECK_EQ(mojo_values.size(), values.size());
 
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
 
   for (size_t i = 0; i < mojo_values.size(); ++i) {
     if (!CreateAllBlobs(values[i].blob_info,
                         &mojo_values[i]->value->blob_or_file_info))
       return;
   }
   callbacks_->SuccessArray(std::move(mojo_values));
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessCursorContinue(
     const IndexedDBKey& key,
     const IndexedDBKey& primary_key,
     ::indexed_db::mojom::ValuePtr value,
     const std::vector<IndexedDBBlobInfo>& blob_info) {
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
 
   if (!value || CreateAllBlobs(blob_info, &value->blob_or_file_info))
     callbacks_->SuccessCursorContinue(key, primary_key, std::move(value));
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessCursorPrefetch(
     const std::vector<IndexedDBKey>& keys,
     const std::vector<IndexedDBKey>& primary_keys,
     std::vector<::indexed_db::mojom::ValuePtr> mojo_values,
     const std::vector<IndexedDBValue>& values) {
   DCHECK_EQ(mojo_values.size(), values.size());
 
   if (!callbacks_)
     return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
 
   for (size_t i = 0; i < mojo_values.size(); ++i) {
     if (!CreateAllBlobs(values[i].blob_info,
                         &mojo_values[i]->blob_or_file_info)) {
       return;
     }
   }
 
   callbacks_->SuccessCursorPrefetch(keys, primary_keys, std::move(mojo_values));
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessKey(
     const IndexedDBKey& value) {
-  if (callbacks_)
-    callbacks_->SuccessKey(value);
+  if (!callbacks_)
+    return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  callbacks_->SuccessKey(value);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccessInteger(int64_t value) {
-  if (callbacks_)
-    callbacks_->SuccessInteger(value);
+  if (!callbacks_)
+    return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  callbacks_->SuccessInteger(value);
 }
 
 void IndexedDBCallbacks::IOThreadHelper::SendSuccess() {
-  if (callbacks_)
-    callbacks_->Success();
+  if (!callbacks_)
+    return;
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return;
+  }
+  callbacks_->Success();
 }
 
 std::string IndexedDBCallbacks::IOThreadHelper::CreateBlobData(
     const IndexedDBBlobInfo& blob_info) {
   if (!blob_info.uuid().empty()) {
     // We're sending back a live blob, not a reference into our backing store.
     return dispatcher_host_->HoldBlobData(blob_info);
   }
   scoped_refptr<ShareableFileReference> shareable_file =
       ShareableFileReference::Get(blob_info.file_path());
   if (!shareable_file) {
     shareable_file = ShareableFileReference::GetOrCreate(
         blob_info.file_path(),
         ShareableFileReference::DONT_DELETE_ON_FINAL_RELEASE,
         dispatcher_host_->context()->TaskRunner());
     if (!blob_info.release_callback().is_null())
       shareable_file->AddFinalReleaseCallback(blob_info.release_callback());
   }
   return dispatcher_host_->HoldBlobData(blob_info);
 }
 
 bool IndexedDBCallbacks::IOThreadHelper::CreateAllBlobs(
     const std::vector<IndexedDBBlobInfo>& blob_info,
     std::vector<::indexed_db::mojom::BlobInfoPtr>* blob_or_file_info) {
+  if (!dispatcher_host_) {
+    OnConnectionError();
+    return false;
+  }
   IDB_TRACE("IndexedDBCallbacks::CreateAllBlobs");
   DCHECK_EQ(blob_info.size(), blob_or_file_info->size());
   if (!dispatcher_host_->blob_storage_context())
     return false;
   for (size_t i = 0; i < blob_info.size(); ++i)
     (*blob_or_file_info)[i]->uuid = CreateBlobData(blob_info[i]);
   return true;
 }
 
 void IndexedDBCallbacks::IOThreadHelper::OnConnectionError() {
   callbacks_.reset();
   dispatcher_host_ = nullptr;
 }
 
 }  // namespace content