Allow to clear session and local storage when not backed on disk

content/browser/dom_storage/dom_storage_namespace.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_namespace.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "content/browser/dom_storage/dom_storage_area.h"
@@ skipping 165 matching lines @@
   return area_count;
 }
 
 void DOMStorageNamespace::OnMemoryDump(
     base::trace_event::ProcessMemoryDump* pmd) {
   DCHECK(task_runner_->IsRunningOnPrimarySequence());
   for (const auto& it : areas_)
     it.second.area_->OnMemoryDump(pmd);
 }
 
+void DOMStorageNamespace::GetOriginsWithAreas(
+    std::vector<GURL>* origins) const {
+  origins->clear();
+  for (const auto& entry : areas_)
+    origins->push_back(entry.first);
+}
+
 DOMStorageNamespace::AreaHolder*
 DOMStorageNamespace::GetAreaHolder(const GURL& origin) {
   AreaMap::iterator found = areas_.find(origin);
   if (found == areas_.end())
     return NULL;
   return &(found->second);
 }
 
 // AreaHolder
 
 DOMStorageNamespace::AreaHolder::AreaHolder()
     : open_count_(0) {
 }
 
 DOMStorageNamespace::AreaHolder::AreaHolder(
     DOMStorageArea* area, int count)
     : area_(area), open_count_(count) {
 }
 
 DOMStorageNamespace::AreaHolder::AreaHolder(const AreaHolder& other) = default;
 
 DOMStorageNamespace::AreaHolder::~AreaHolder() {
 }
 
 }  // namespace content