Send a message to the renderers when content settings change.

chrome/browser/host_content_settings_map.h

 // Copyright (c) 2010 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.
 
 // Maps hostnames to custom content settings.  Written on the UI thread and read
 // on any thread.  One instance per profile.
 
 #ifndef CHROME_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 #define CHROME_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/lock.h"
 #include "base/ref_counted.h"
 #include "chrome/common/content_settings.h"
 
 class DictionaryValue;
 class PrefService;
 class Profile;
 
 class HostContentSettingsMap
     : public base::RefCountedThreadSafe<HostContentSettingsMap> {
  public:
+  // Details for the CONTENT_SETTINGS_CHANGED notification. This is sent when
+  // content settings change for at least one host. If settings change for more
+  // than one host in one user interaction, this will usually send a single
+  // notification with a wildcard host field instead of one notification for
+  // each host.
+  class ContentSettingsDetails {
+   public:
+    ContentSettingsDetails(const std::string& host) : host_(host) {}
+    // The host whose settings have changed. Empty if many hosts are affected
+    // (e.g. if the default settings have changed).
+    const std::string& host() { return host_; }
+
+   private:
+    std::string host_;
+  };
+
   typedef std::pair<std::string, ContentSetting> HostSettingPair;
   typedef std::vector<HostSettingPair> SettingsForOneType;
 
   explicit HostContentSettingsMap(Profile* profile);
 
   static void RegisterUserPrefs(PrefService* prefs);
 
   // Returns the default setting for a particular content type.
   //
   // This may be called on any thread.
@@ skipping 69 matching lines @@
   void GetSettingsFromDictionary(const DictionaryValue* dictionary,
                                  ContentSettings* settings);
 
   // Forces the default settings to be explicitly set instead of themselves
   // being CONTENT_SETTING_DEFAULT.
   void ForceDefaultsToBeExplicit();
 
   // Returns true if |settings| consists entirely of CONTENT_SETTING_DEFAULT.
   bool AllDefault(const ContentSettings& settings) const;
 
+  // Informs observers that content settings have changed. Make sure that
+  // |lock_| is not held when calling this, as listeners will usually call one
+  // of the GetSettings functions in response, which would then lead to a
+  // mutex deadlock.
+  void NotifyObservers(const std::string& host);
+
   // The profile we're associated with.
   Profile* profile_;
 
   // Copies of the pref data, so that we can read it on the IO thread.
   ContentSettings default_content_settings_;
   HostContentSettings host_content_settings_;
 
   // Misc global settings.
   bool block_third_party_cookies_;
 
   // Used around accesses to the settings objects to guarantee thread safety.
   mutable Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(HostContentSettingsMap);
 };
 
 #endif  // CHROME_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_