[fsp] Allow to create multiple observers for a directory, up to one per origin.

chrome/browser/chromeos/file_system_provider/observed_entry.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OBSERVED_ENTRY_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OBSERVED_ENTRY_H_
 
 #include <map>
+#include <set>
 #include <string>
 
 #include "base/files/file_path.h"
+#include "url/gurl.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
 struct ObservedEntry;
+struct Subscriber;
 
 // Key for storing an observed entry in the map. There may be two observers
 // per path, as long as one is recursive, and the other one not.
 struct ObservedEntryKey {
   ObservedEntryKey(const base::FilePath& entry_path, bool recursive);
   ~ObservedEntryKey();
 
   struct Comparator {
     bool operator()(const ObservedEntryKey& a, const ObservedEntryKey& b) const;
   };
 
   base::FilePath entry_path;
   bool recursive;
 };
 
 // List of observed entries.
 typedef std::map<ObservedEntryKey, ObservedEntry, ObservedEntryKey::Comparator>
     ObservedEntries;
 
+// Map of subscribers for notifications about an observed entry.
+typedef std::map<GURL, Subscriber> Subscribers;
+
+// Represents a subscriber for notification about an observed entry. There may
+// be up to one subscriber per origin for the same observed entry.
+struct Subscriber {
+  Subscriber();
+  ~Subscriber();
+
+  // Origin of the subscriber.
+  GURL origin;
+
+  // Whether the subscriber should be restored after shutdown or not.
+  bool persistent;
+};
+
 // Represents an observed entry on a file system.
 struct ObservedEntry {
   ObservedEntry();
   ~ObservedEntry();
 
+  // Map of subscribers for notifications of the observed entry.
+  Subscribers subscribers;
+
+  // Path of the observed entry.
   base::FilePath entry_path;
+
+  // Whether observing is recursive or not.
   bool recursive;
+
+  // Tag of the last notification for this observed entry. May be empty if not
+  // supported.
   std::string last_tag;
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OBSERVED_ENTRY_H_