Move UI dependency from WebDataService to WebDataServiceFactory.

chrome/browser/api/webdata/web_data_service_base.h

Index: chrome/browser/api/webdata/web_data_service_base.h
diff --git a/chrome/browser/api/webdata/web_data_service_base.h b/chrome/browser/api/webdata/web_data_service_base.h
index 9a6f92640cf7bc591a3da420cbd86f2be8f6b198..15bbfff2f276ae04f3da89b5cb331e723c50d529 100644
--- a/chrome/browser/api/webdata/web_data_service_base.h
+++ b/chrome/browser/api/webdata/web_data_service_base.h
@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_API_WEBDATA_WEB_DATA_SERVICE_BASE_H_
 #define CHROME_BROWSER_API_WEBDATA_WEB_DATA_SERVICE_BASE_H_
 
+#include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ -27,7 +28,15 @@ class WebDataServiceBase
   // All requests return an opaque handle of the following type.
   typedef int Handle;
 
-  WebDataServiceBase();
+  // Users of this class may provide a callback to handle errors
+  // (e.g. by showing a UI). The callback is called only on error, and
+  // takes a single parameter, the sql::InitStatus value from trying
+  // to open the database.
+  typedef base::Callback<void(sql::InitStatus)> ProfileErrorCallback;

[Cait (Slow), 2013/03/18 16:16:37]

ATM we have a WebDataServiceBase::ProfileErrorCallback and a
WebDatabaseService::InitCallback type which are defined identically. We should
probably merge them and name them something more general, but I think this can
wait for a later CL. 

[Jói, 2013/03/18 23:21:23]

Yes, I think we should wait for all the pieces to fall in place before deciding
whether to combine them. I've added a TODO here.

+
+  // |callback| will only be invoked on error, and only if
+  // ||callback.is_null()| evaluates to true.

[Cait (Slow), 2013/03/18 16:16:37]

nit: |callback.is_null() --> !callback.is_null()

[Jói, 2013/03/18 23:21:23]

Thanks for the catch. Switched "evaluates to true" to "evaluates to false"
instead.

+  WebDataServiceBase(const ProfileErrorCallback& callback);
 
   // Cancel any pending request. You need to call this method if your
   // WebDataServiceConsumer is about to be deleted.
@@ -74,6 +83,8 @@ class WebDataServiceBase
       content::BrowserThread::UI>;
   friend class base::DeleteHelper<WebDataServiceBase>;
 
+  ProfileErrorCallback profile_error_callback_;
+
   void DBInitFailed(sql::InitStatus sql_status);
   void NotifyDatabaseLoadedOnUIThread();
   void DatabaseInitOnDB(sql::InitStatus status);