Purge browser cache for dom storage in a smarter way

content/browser/dom_storage/dom_storage_area.h

 // 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.
 
 #ifndef CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/nullable_string16.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
+#include "content/common/dom_storage/dom_storage_map.h"
 #include "content/common/dom_storage/dom_storage_types.h"
 #include "url/gurl.h"
 
 namespace base {
 namespace trace_event {
 class ProcessMemoryDump;
 }
 }
 
 namespace content {
 
 class DOMStorageDatabaseAdapter;
-class DOMStorageMap;
 class DOMStorageTaskRunner;
 class SessionStorageDatabase;
 
 // Container for a per-origin Map of key/value pairs potentially
 // backed by storage on disk and lazily commits changes to disk.
 // See class comments for DOMStorageContextImpl for a larger overview.
 class CONTENT_EXPORT DOMStorageArea
     : public base::RefCountedThreadSafe<DOMStorageArea> {
 
  public:
@@ skipping 14 matching lines @@
 
   // Session storage. Backed on disk if |session_storage_backing| is not NULL.
   DOMStorageArea(int64_t namespace_id,
                  const std::string& persistent_namespace_id,
                  const GURL& origin,
                  SessionStorageDatabase* session_storage_backing,
                  DOMStorageTaskRunner* task_runner);
 
   const GURL& origin() const { return origin_; }
   int64_t namespace_id() const { return namespace_id_; }
+  size_t map_usage_in_bytes() const { return map_ ? map_->bytes_used() : 0; }
 
   // Writes a copy of the current set of values in the area to the |map|.
   void ExtractValues(DOMStorageValuesMap* map);
 
   unsigned Length();
   base::NullableString16 Key(unsigned index);
   base::NullableString16 GetItem(const base::string16& key);
   bool SetItem(const base::string16& key, const base::string16& value,
                base::NullableString16* old_value);
   bool RemoveItem(const base::string16& key, base::string16* old_value);
@@ skipping 111 matching lines @@
   base::TimeTicks start_time_;
   RateLimiter data_rate_limiter_;
   RateLimiter commit_rate_limiter_;
 
   DISALLOW_COPY_AND_ASSIGN(DOMStorageArea);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_