Fix for Bug 50726 "Save extension list and "winning" prefs from extensions"

chrome/browser/extensions/extension_prefs.h

Index: chrome/browser/extensions/extension_prefs.h
diff --git a/chrome/browser/extensions/extension_prefs.h b/chrome/browser/extensions/extension_prefs.h
index 6245edac68f2ea73e5c6496f1088e1acb0f99533..6adb5530597952d32c98b770387e118b83cc0579 100644
--- a/chrome/browser/extensions/extension_prefs.h
+++ b/chrome/browser/extensions/extension_prefs.h
@@ -19,6 +19,18 @@
 // Class for managing global and per-extension preferences.
 // This class is instantiated by ExtensionsService, so it should be accessed
 // from there.
+//
+// This class distinguishes the following kinds of preferences:
+// - global preferences:
+//       internal state for the extension system in general, not associated
+//       with an individual extension, such as lastUpdateTime.
+// - per-extension preferences:
+//       meta-preferences describing properties of the extension like
+//       installation time, whether the extension is enabled, etc.
+// - extension controlled preferences:
+//       global preferences that an individual extension wants to set;
+//       these are arbitrary preferences that are controlled by other
+//       sub-systems.
 class ExtensionPrefs {
  public:
   // Key name for a preference that keeps track of per-extension settings. This
@@ -28,6 +40,12 @@ class ExtensionPrefs {
 
   typedef std::vector<linked_ptr<ExtensionInfo> > ExtensionsInfo;
 
+  // Vector containing identifiers for preferences.
+  typedef std::vector<std::string> PrefKeySet;
+
+  // Vector containing identifiers for extensions.
+  typedef std::vector<std::string> ExtensionIdSet;
+
   // This enum is used for the launch type the user wants to use for an
   // application.
   // Do not remove items or re-order this enum as it is used in preferences
@@ -39,7 +57,9 @@ class ExtensionPrefs {
     LAUNCH_WINDOW
   };
 
-  explicit ExtensionPrefs(PrefService* prefs, const FilePath& root_dir_);
+  explicit ExtensionPrefs(Profile* profile,
+                          PrefService* prefs,
+                          const FilePath& root_dir);

[Mattias Nissler (ping if slow), 2010/12/01 10:36:36]

Can we guarantee that the ExtensionPrefStore outlives ExtensionPrefs? In that
case I'd vote for passing the ExtensionPrefs pointer here instead of the whole
profile. If not, passing both profile and prefs is redundant, since we can
always call profile->GetPrefs() to get to the PrefService.

[battre (please use the other), 2010/12/01 17:44:38]

Done. Moved PrefService in ProfileImpl accordingly.

   ~ExtensionPrefs();
 
   // Returns a copy of the Extensions prefs.
@@ -74,11 +94,14 @@ class ExtensionPrefs {
                               bool external_uninstall);
 
   // Returns the state (enabled/disabled) of the given extension.
-  Extension::State GetExtensionState(const std::string& extension_id);
+  Extension::State GetExtensionState(const std::string& extension_id) const;
 
   // Called to change the extension's state when it is enabled/disabled.
   void SetExtensionState(const Extension* extension, Extension::State);
 
+  // Returns all installed and enabled extensions
+  void GetEnabledExtensions(ExtensionIdSet* out) const;
+
   // Getter and setter for browser action visibility.
   bool GetBrowserActionVisibility(const Extension* extension);
   void SetBrowserActionVisibility(const Extension* extension, bool visible);
@@ -232,11 +255,23 @@ class ExtensionPrefs {
                         const std::string& data);
   std::string GetUpdateUrlData(const std::string& extension_id);
 
+  // Sets a preference value that is controlled by the extension. In other
+  // words, this is not a pref value *about* the extension but something
+  // global the extension wants to override.
+  void SetExtensionControlledPref(const std::string& extension_id,
+                                  const std::string& pref_key,
+                                  Value* value);
+
   static void RegisterUserPrefs(PrefService* prefs);
 
   // The underlying PrefService.
   PrefService* pref_service() const { return prefs_; }
 
+ protected:
+  // For unit testing. Enables injecting an artificial clock that is used
+  // to query the current time, when an extension is installed.
+  virtual base::Time GetCurrentTime() const;
+
  private:
   // Converts absolute paths in the pref to paths relative to the
   // install_directory_.
@@ -296,6 +331,11 @@ class ExtensionPrefs {
   // Same as above, but returns NULL if it doesn't exist.
   DictionaryValue* GetExtensionPref(const std::string& id) const;
 
+  // Returns the dictionary of preferences controlled by the specified extension
+  // or NULL if unknown. All entries in the dictionary contain non-expanded
+  // paths.
+  DictionaryValue* GetExtensionControlledPrefs(const std::string& id) const;
+
   // Serializes the data and schedules a persistent save via the |PrefService|.
   // Additionally fires a PREF_CHANGED notification with the top-level
   // |kExtensionsPref| path set.
@@ -313,6 +353,35 @@ class ExtensionPrefs {
   base::Time LastPingDayImpl(const DictionaryValue* dictionary) const;
   void SetLastPingDayImpl(const base::Time& time, DictionaryValue* dictionary);
 
+  // Helper method to acquire the installation time of an extension

[Mattias Nissler (ping if slow), 2010/12/01 10:36:36]

Missing period.

[battre (please use the other), 2010/12/01 17:44:38]

Done.

+  base::Time GetInstallTime(const std::string& extension_id) const;
+
+  // Fix missing preference entries in the extensions that are were introduced
+  // in a later Chrome version.
+  void FixMissingPrefs(const ExtensionIdSet& extension_ids);
+
+  // Installs the persistent extension preferences into |prefs_|'s extension
+  // pref store.
+  void InstallPersistedExtensionControlledPrefs();
+
+  // Returns the extension controlled preference value of the extension that was
+  // installed most recently.
+  const Value* WinningExtensionControlledPrefValue(const std::string& key)
+      const;

[Mattias Nissler (ping if slow), 2010/12/01 10:36:36]

"If your function is const, the const keyword should be on the same line as the
last parameter"

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Function_Decla...

[battre (please use the other), 2010/12/01 17:44:38]

Done.

+
+  // Find the most recently installed extension that defines a preference
+  // for |pref_key|, then store its value in the PrefValueStore's extension pref
+  // store and send notifications to observers in case the value changed.
+  void UpdateWinningPref(const std::string& pref_key,
+                         bool suppressNotification);
+
+  // Retrieves a list of preference keys that the specified extension
+  // intents to manage.
+  void GetExtensionControlledPrefKeys(const std::string& extension_id,
+                                      PrefKeySet *out) const;
+
+  Profile* profile_;
+
   // The pref service specific to this set of extension prefs.
   PrefService* prefs_;