Review of attachment 337433 [details] [review]:

::: gdata/services/documents/gdata-documents-document.c
@@ -399,3 @@
 	if (download_uri == NULL) {
 		g_set_error (error, GDATA_SERVICE_ERROR, GDATA_SERVICE_ERROR_NOT_FOUND,
-		             _("Unknown or unsupported document export format ‘%s’."), export_format);

That one’s already Unicode. Please don’t change the single quotes to double quotes.

::: gdata/services/documents/gdata-documents-service.c
@@ +944,3 @@
 	if (g_type_is_a (new_document_type, GDATA_TYPE_DOCUMENTS_DOCUMENT) == FALSE) {
 		g_set_error (error, GDATA_DOCUMENTS_SERVICE_ERROR, GDATA_DOCUMENTS_SERVICE_ERROR_INVALID_CONTENT_TYPE,
+		             _("The content type of the supplied document (“%s”) could not be recognized."),

Please use single Unicode quotes.

::: gdata/services/freebase/gdata-freebase-service.c
@@ +477,3 @@
 			     GDATA_SERVICE_ERROR,
 			     GDATA_SERVICE_ERROR_BAD_QUERY_PARAMETER,
+			     _("Property “%s” does not hold an image"),

Please use single Unicode quotes.

This comment applies throughout the patch; even for the ones which were originally double ASCII quotes — let’s use this opportunity to standardise libgdata on single quotes.

The HIG page doesn’t actually specify whether double or single quotes should be used, it just specifies that double Unicode quotes should be used instead of double ASCII quotes.

Created attachment 337442 [details] [review]
Use Unicode in translatable strings

Review of attachment 337442 [details] [review]:

Great, thanks. Please push to master.

Comment on attachment 337442 [details] [review]
Use Unicode in translatable strings

Pushed, thank you.