mojo leveldb: Add support to use in memory database.

content/browser/dom_storage/dom_storage_context_wrapper.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 "content/browser/dom_storage/dom_storage_context_wrapper.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 113 matching lines @@
 
   base::WeakPtrFactory<MojoState> weak_ptr_factory_;
 };
 
 void DOMStorageContextWrapper::MojoState::OpenLocalStorage(
     const url::Origin& origin,
     LevelDBWrapperRequest request) {
   // If we don't have a specific subdirectory where we want to put our data
   // (ie, we're in incognito mode), just bind the storage with a null leveldb_
   // database.
   if (subdirectory_.empty()) {

[michaeln, 2016/03/22 21:15:10]

did you mean to delete this block now so we always have a database_?

     BindLocalStorage(origin, std::move(request));
     return;
   }
 
   // If we don't have a filesystem_connection_, we'll need to establish one.
   if (connection_state_ == NO_CONNECTION) {
     profile_app_connection_ = MojoAppConnection::Create(
         mojo_user_id_, "mojo:profile", kBrowserMojoAppUrl);
-    profile_app_connection_->GetInterface(&profile_service_);
 
-    profile_service_->GetSubDirectory(
-        mojo::String::From(subdirectory_.AsUTF8Unsafe()),
-        GetProxy(&directory_),
-        base::Bind(&MojoState::OnDirectoryOpened,
-                   weak_ptr_factory_.GetWeakPtr()));
     connection_state_ = CONNECTION_IN_PROGRESS;
+
+    if (!subdirectory_.empty()) {
+      // We were given a subdirectory to write to. Get it and use a disk backed
+      // database.
+      profile_app_connection_->GetInterface(&profile_service_);
+      profile_service_->GetSubDirectory(
+          mojo::String::From(subdirectory_.AsUTF8Unsafe()),
+          GetProxy(&directory_),
+          base::Bind(&MojoState::OnDirectoryOpened,
+                     weak_ptr_factory_.GetWeakPtr()));
+    } else {
+      // We were not given a subdirectory. Use a memory backed database.
+      profile_app_connection_->GetInterface(&leveldb_service_);
+      leveldb_service_->OpenInMemory(
+          GetProxy(&database_),
+          base::Bind(&MojoState::OnDatabaseOpened,
+                     weak_ptr_factory_.GetWeakPtr()));
+    }
   }
 
   if (connection_state_ == CONNECTION_IN_PROGRESS) {
     // Queue this OpenLocalStorage call for when we have a level db pointer.
     on_database_opened_callbacks_.push_back(
         base::Bind(&MojoState::BindLocalStorage, weak_ptr_factory_.GetWeakPtr(),
                    origin, base::Passed(&request)));
     return;
   }
 
@@ skipping 168 matching lines @@
       FROM_HERE, DOMStorageTaskRunner::PRIMARY_SEQUENCE,
       base::Bind(&DOMStorageContextImpl::Flush, context_));
 }
 
 void DOMStorageContextWrapper::OpenLocalStorage(const url::Origin& origin,
                                                 LevelDBWrapperRequest request) {
   mojo_state_->OpenLocalStorage(origin, std::move(request));
 }
 
 }  // namespace content