Persist sessionStorage on disk.

content/browser/dom_storage/dom_storage_context_impl.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/dom_storage/dom_storage_context_impl.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/message_loop_proxy.h"
 #include "content/public/browser/browser_thread.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
 #include "webkit/database/database_util.h"
 #include "webkit/dom_storage/dom_storage_area.h"
 #include "webkit/dom_storage/dom_storage_context.h"
 #include "webkit/dom_storage/dom_storage_task_runner.h"
 #include "webkit/glue/webkit_glue.h"
 
 using content::BrowserThread;
 using content::DOMStorageContext;
 using dom_storage::DomStorageArea;
 using dom_storage::DomStorageContext;
 using dom_storage::DomStorageTaskRunner;
 using dom_storage::DomStorageWorkerPoolTaskRunner;
 using webkit_database::DatabaseUtil;
 
 namespace {
 
 const char kLocalStorageDirectory[] = "Local Storage";
+const char kSessionStorageDirectory[] = "Session Storage";
 
 // TODO(michaeln): Fix the content layer api, FilePaths and
 // string16 origin_ids are just wrong. Then get rid of
 // this conversion non-sense. Most of the includes are just
 // to support that non-sense.
 
 GURL OriginIdToGURL(const string16& origin_id) {
   return DatabaseUtil::GetOriginFromIdentifier(origin_id);
 }
 
@@ skipping 40 matching lines @@
 
 DOMStorageContextImpl::DOMStorageContextImpl(
     const FilePath& data_path,
     quota::SpecialStoragePolicy* special_storage_policy) {
   base::SequencedWorkerPool* worker_pool = BrowserThread::GetBlockingPool();
   // TODO(marja): Pass a nonempty session storage directory when session storage
   // is backed on disk.
   context_ = new dom_storage::DomStorageContext(
       data_path.empty() ?
           data_path : data_path.AppendASCII(kLocalStorageDirectory),
-      FilePath(),  // Empty session storage directory.
+      data_path.empty() ?
+          data_path : data_path.AppendASCII(kSessionStorageDirectory),

[michaeln, 2012/05/16 08:10:55]

until we work out how the higher level session restore logic interfaces with
this lower level logic, and it's ready to utilize that interface, it'd probably
be good to keep this as an empty path... we can turn this on when things are
ready from end to end.

[marja, 2012/05/30 11:46:19]

I would have liked to put this "save session state" behind a command line flag,
but the information about command line flags seems to be so far away here...

I added BrowserContext::ShouldSaveSessionStorageOnDisk here, and the version
overwritten by ProfileImpl reads the command line flag. Wdyt?

       special_storage_policy,
       new DomStorageWorkerPoolTaskRunner(
           worker_pool,
           worker_pool->GetNamedSequenceToken("dom_storage_primary"),
           worker_pool->GetNamedSequenceToken("dom_storage_commit"),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)));
 }
 
 DOMStorageContextImpl::~DOMStorageContextImpl() {
 }
@@ skipping 78 matching lines @@
 int64 DOMStorageContextImpl::LeakyCloneSessionStorage(
     int64 existing_namespace_id) {
   DCHECK(context_);
   int64 clone_id = context_->AllocateSessionId();
   context_->task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&DomStorageContext::CloneSessionNamespace, context_,
                  existing_namespace_id, clone_id));
   return clone_id;
 }