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

chrome/browser/chromeos/file_system_provider/observed_entry.h

Index: chrome/browser/chromeos/file_system_provider/observed_entry.h
diff --git a/chrome/browser/chromeos/file_system_provider/observed_entry.h b/chrome/browser/chromeos/file_system_provider/observed_entry.h
index f34d1b073cdac94353fd9b7a835c2340ff34c3b7..b69b4981658e28ea847036dd423988b17f5aea26 100644
--- a/chrome/browser/chromeos/file_system_provider/observed_entry.h
+++ b/chrome/browser/chromeos/file_system_provider/observed_entry.h
@@ -6,14 +6,17 @@
 #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.
@@ -33,13 +36,38 @@ struct ObservedEntryKey {
 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;
 };