Extension Settings API: move the API functions into an object SettingsNamepace,

chrome/browser/extensions/settings/settings_frontend.h

Index: chrome/browser/extensions/settings/settings_frontend.h
diff --git a/chrome/browser/extensions/settings/settings_frontend.h b/chrome/browser/extensions/settings/settings_frontend.h
index 66cb48884debb985107b2137d9efe306390918dc..04c94bc08739661300323db7863abbebb9c891d4 100644
--- a/chrome/browser/extensions/settings/settings_frontend.h
+++ b/chrome/browser/extensions/settings/settings_frontend.h
@@ -14,6 +14,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list_threadsafe.h"
 #include "chrome/browser/extensions/settings/settings_leveldb_storage.h"
+#include "chrome/browser/extensions/settings/settings_namespace.h"
 #include "chrome/browser/extensions/settings/settings_observer.h"
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "content/public/browser/notification_observer.h"
@@ -34,8 +35,7 @@ class SettingsFrontend {
   static SettingsFrontend* Create(Profile* profile);
 
   static SettingsFrontend* Create(
-      // Ownership taken.
-      SettingsStorageFactory* storage_factory,
+      const scoped_refptr<SettingsStorageFactory>& storage_factory,
       // Owership NOT taken.
       Profile* profile);
 
@@ -53,7 +53,9 @@ class SettingsFrontend {
   // |extension_id|.  If there is no extension with that ID, the storage area
   // will be NULL.
   void RunWithStorage(
-      const std::string& extension_id, const StorageCallback& callback);
+      const std::string& extension_id,
+      settings_namespace::Namespace settings_namespace,
+      const StorageCallback& callback);
 
   // Deletes the settings for an extension (on the FILE thread).
   void DeleteStorageSoon(const std::string& extension_id);
@@ -62,25 +64,8 @@ class SettingsFrontend {
   scoped_refptr<SettingsObserverList> GetObservers();
 
  private:
-  // Settings change Observer which forwards changes on to the extension
-  // processes for |profile| and its incognito partner if it exists.
-  class DefaultObserver : public SettingsObserver {
-   public:
-    explicit DefaultObserver(Profile* profile);
-    virtual ~DefaultObserver();
-
-    // SettingsObserver implementation.
-    virtual void OnSettingsChanged(
-        const std::string& extension_id,
-        const std::string& change_json) OVERRIDE;
-
-   private:
-    Profile* const profile_;
-  };
-
   SettingsFrontend(
-      // Ownership taken.
-      SettingsStorageFactory* storage_factory,
+      const scoped_refptr<SettingsStorageFactory>& storage_factory,
       // Ownership NOT taken.
       Profile* profile);
 
@@ -91,11 +76,20 @@ class SettingsFrontend {
   scoped_refptr<SettingsObserverList> observers_;
 
   // Observer for |profile_|.
-  DefaultObserver default_observer_;
-
-  // Ref-counted container for the SettingsBackend object.
-  class Core;
-  scoped_refptr<Core> core_;
+  scoped_ptr<SettingsObserver> profile_observer_;
+
+  // Ref-counted container for each SettingsBackend object.  There are 4: an
+  // apps and an extensions Backend for the LOCAL namespace, and likewise for
+  // the SYNC namespace.  They only differ in what directory the database for
+  // each exists in (and the Backends in the SYNC namespace happen to be
+  // returned from RunWithSyncableService).
+  //
+  // |backends_| is a map from namespace to app/extension Backend pair (as a map
+  // from "is an app" to Backend).
+  class BackendWrapper;

[not at google - send to devlin, 2011/11/23 02:24:43]

I tried a bunch of things and this was just... the nicest I could think of. 
Other ideas welcome.

[Matt Perry, 2011/11/23 03:35:05]

How about just being explicit?

struct Backends {
  scoped_refptr<BackendWrapper> app_backend;
  scoped_refptr<BackendWrapper> extension_backend;
};

Backends local_backends;
Backends sync_backends;

and maybe a helper function GetBackend(namespace, is_app)

[not at google - send to devlin, 2011/11/23 11:04:52]

Ok, I like the map<settings_namespace::Namespace> but mapping that to a Backends
is nicer than what I have.  Done.

+  std::map<
+      settings_namespace::Namespace,
+      std::map<bool, scoped_refptr<BackendWrapper> > > backends_;
 
   DISALLOW_COPY_AND_ASSIGN(SettingsFrontend);
 };