Linux: support append to password list in the GNOME keyring backend to fix initial password sync.

chrome/browser/password_manager/native_backend_gnome_x.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/password_manager/native_backend_gnome_x.h"
 
 #include <dlfcn.h>
 #include <gnome-keyring.h>
 
 #include <map>
@@ skipping 364 matching lines @@
 
 GnomeKeyringResult GKRMethod::WaitResult() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
   event_.Wait();
   return result_;
 }
 
 GnomeKeyringResult GKRMethod::WaitResult(PasswordFormList* forms) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
   event_.Wait();
-  forms->swap(forms_);
+  if (forms->empty()) {
+    // Normal case. Avoid extra allocation by swapping.
+    forms->swap(forms_);

[Evan Martin, 2011/08/23 14:36:07]

Is this performance critical?  I wonder if it's worth the extra code.  It seems
this is a vector of pointers, so either way the total amount of data being moved
around is on the order of 200 bytes.

[Mike Mammarella, 2011/08/23 19:40:20]

No, it's not performance critical. It would probably be fine to just do the copy
always. On the other hand it's really not much code and it "feels" better to me
to avoid the unnecessary copy since it's so easy to do. If you want I'll remove
it but otherwise I'm inclined to leave it.

+  } else {
+    // Rare case. Append forms_ to *forms.
+    forms->insert(forms->end(), forms_.begin(), forms_.end());
+    forms_.clear();
+  }
   return result_;
 }
 
 // static
 void GKRMethod::OnOperationDone(GnomeKeyringResult result, gpointer data) {
   GKRMethod* method = static_cast<GKRMethod*>(data);
   method->result_ = result;
   method->event_.Signal();
 }
 
@@ skipping 331 matching lines @@
     // Each other profile must be able to migrate the shared data as well,
     // so we must leave it alone. After a few releases, we'll add code to
     // delete them, and eventually remove this migration code.
     // TODO(mdm): follow through with the plan above.
     PasswordStoreX::SetPasswordsUseLocalProfileId(prefs_);
   } else {
     // We failed to migrate for some reason. Use the old app string.
     app_string_ = kGnomeKeyringAppString;
   }
 }