Replace WebDatabaseObserver with callbacks

components/webdata/common/web_database_service.cc

Index: components/webdata/common/web_database_service.cc
diff --git a/components/webdata/common/web_database_service.cc b/components/webdata/common/web_database_service.cc
index a1b18895e84c0f788c884b8a7231e78f7319a7fb..313707301ac5cb676266d85bc15ab65237d5e89b 100644
--- a/components/webdata/common/web_database_service.cc
+++ b/components/webdata/common/web_database_service.cc
@@ -40,7 +40,8 @@ class WebDatabaseService::BackendDelegate :
 WebDatabaseService::WebDatabaseService(
     const base::FilePath& path)
     : path_(path),
-      weak_ptr_factory_(this) {
+      weak_ptr_factory_(this),
+      db_loaded_(false) {
   // WebDatabaseService should be instantiated on UI thread.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   // WebDatabaseService requires DB thread if instantiated.
@@ -68,6 +69,7 @@ void WebDatabaseService::LoadDatabase() {
 }
 
 void WebDatabaseService::UnloadDatabase() {
+  db_loaded_ = false;
   if (!wds_backend_.get())
     return;
   BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
@@ -76,6 +78,7 @@ void WebDatabaseService::UnloadDatabase() {
 }
 
 void WebDatabaseService::ShutdownDatabase() {
+  db_loaded_ = false;
   if (!wds_backend_.get())
     return;
   weak_ptr_factory_.InvalidateWeakPtrs();
@@ -140,24 +143,29 @@ void WebDatabaseService::CancelRequest(WebDataServiceBase::Handle h) {
   wds_backend_->request_manager()->CancelRequest(h);
 }
 
-void WebDatabaseService::AddObserver(WebDatabaseObserver* observer) {
-  observer_list_.AddObserver(observer);
+void WebDatabaseService::RegisterDBLoadedCallback(
+    const base::Callback<void(void)>& callback) {
+  pending_callbacks_.push_back(callback);

[Cait (Slow), 2013/06/05 19:14:48]

I'm wondering if I should handle callbacks added post-DB-load (i.e. call them
immediately). Doing so would require storing some info about the DB state (did
we try to load it and fail? why did it fail? etc) in this class which is already
stored in the backend, and this seems a bit redundant. 

Maybe it is sufficient to document that callbacks added after the loading is
finished won't get called (esp. since there is an IsDBLoaded() method)? 

[Jói, 2013/06/06 11:37:17]

I think just documenting is sufficient.

 }
 
-void WebDatabaseService::RemoveObserver(WebDatabaseObserver* observer) {
-  observer_list_.RemoveObserver(observer);
+void WebDatabaseService::RegisterDBErrorCallback(
+    const base::Callback<void(sql::InitStatus)>& callback) {
+  error_callbacks_.push_back(callback);
 }
 
 void WebDatabaseService::OnDatabaseLoadDone(sql::InitStatus status) {
   if (status == sql::INIT_OK) {
-    // Notify that the database has been initialized.
-    FOR_EACH_OBSERVER(WebDatabaseObserver,
-                      observer_list_,
-                      WebDatabaseLoaded());
+    db_loaded_ = true;
+
+    for (size_t i = 0; i < pending_callbacks_.size(); i++)
+      pending_callbacks_[i].Run();
+
+    pending_callbacks_.clear();
   } else {
     // Notify that the database load failed.
-    FOR_EACH_OBSERVER(WebDatabaseObserver,
-                      observer_list_,
-                      WebDatabaseLoadFailed(status));
+    for (size_t i = 0; i < error_callbacks_.size(); i++)
+      error_callbacks_[i].Run(status);
+
+    error_callbacks_.clear();
   }
 }