Move ownership of AppSorting from ExtensionPrefs to ExtensionSystem

chrome/browser/extensions/chrome_app_sorting.h

Index: chrome/browser/extensions/chrome_app_sorting.h
diff --git a/chrome/browser/extensions/chrome_app_sorting.h b/chrome/browser/extensions/chrome_app_sorting.h
index 2754bc0baaaec978bd273757fbf266e7d40e001f..29f0927c2f88216961089057e3dc795fe812c998 100644
--- a/chrome/browser/extensions/chrome_app_sorting.h
+++ b/chrome/browser/extensions/chrome_app_sorting.h
@@ -27,8 +27,6 @@ class ChromeAppSorting : public AppSorting {
   ~ChromeAppSorting() override;
 
   // AppSorting implementation:
-  void SetExtensionScopedPrefs(ExtensionScopedPrefs* prefs) override;
-  void CheckExtensionScopedPrefs() const override;
   void Initialize(const extensions::ExtensionIdList& extension_ids) override;

[not at google - send to devlin, 2015/07/29 18:22:03]

I'd like to take this off the public interface, and have ChromeAppSorting handle
this itself.

For example, you could the strategy that ExtensionSystem::ready() uses and add
an ExtensionPrefs::ready().

[Marc Treib, 2015/07/30 14:04:12]

Agreed. I'll do this when the remaining stuff is sorted out.

   void FixNTPOrdinalCollisions() override;
   void EnsureValidOrdinals(
@@ -152,7 +150,6 @@ class ChromeAppSorting : public AppSorting {
   // Returns the number of items in |m| visible on the new tab page.
   size_t CountItemsVisibleOnNtp(const AppLaunchOrdinalMap& m) const;
 
-  ExtensionScopedPrefs* extension_scoped_prefs_;  // Weak, owns this instance.
   content::BrowserContext* browser_context_;
 
   // A map of all the StringOrdinal page ordinals mapping to the collections of