Convert AutoBlocker static class to KeyedService.

chrome/browser/permissions/permission_blacklist_client.h

Index: chrome/browser/permissions/permission_blacklist_client.h
diff --git a/chrome/browser/permissions/permission_blacklist_client.h b/chrome/browser/permissions/permission_blacklist_client.h
index 2d1666e00af5925ebd567bc4128e95c95b8eb7fe..239614362639a43dbec14e4be4c2a5fce6400df3 100644
--- a/chrome/browser/permissions/permission_blacklist_client.h
+++ b/chrome/browser/permissions/permission_blacklist_client.h
@@ -31,6 +31,9 @@ class PermissionBlacklistClient
       public base::RefCountedThreadSafe<PermissionBlacklistClient>,
       public content::WebContentsObserver {
  public:
+  // |callback| will not be called if |web_contents| is destroyed. Thus if the
+  // callback is run, the profile associated with |web_contents| is guaranteed
+  // to be alive.
   static void CheckSafeBrowsingBlacklist(
       scoped_refptr<safe_browsing::SafeBrowsingDatabaseManager> db_manager,
       content::PermissionType permission_type,