Print a stacktrace when we can't find a string resource (on Windows).

app/resource_bundle_win.cc

Index: app/resource_bundle_win.cc
diff --git a/app/resource_bundle_win.cc b/app/resource_bundle_win.cc
index 35264816f9afa2a9770b180019fe80dc3402c6a7..fc9e36027f78dcb24d5e209b5fc13f870c2cd3c5 100644
--- a/app/resource_bundle_win.cc
+++ b/app/resource_bundle_win.cc
@@ -9,6 +9,7 @@
 #include "app/app_paths.h"
 #include "app/gfx/font.h"
 #include "app/l10n_util.h"
+#include "base/debug_util.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
@@ -133,6 +134,7 @@ string16 ResourceBundle::GetLocalizedString(int message_id) {
   // If for some reason we were unable to load a resource dll, return an empty
   // string (better than crashing).
   if (!locale_resources_data_) {
+    StackTrace().PrintBacktrace();  // See http://crbug.com/21925.
     LOG(WARNING) << "locale resources are not loaded";
     return string16();
   }
@@ -149,6 +151,7 @@ string16 ResourceBundle::GetLocalizedString(int message_id) {
     image = AtlGetStringResourceImage(_AtlBaseModule.GetModuleInstance(),
                                       message_id);
     if (!image) {
+      StackTrace().PrintBacktrace();  // See http://crbug.com/21925.
       NOTREACHED() << "unable to find resource: " << message_id;
       return std::wstring();
     }