Eliminate silently letting errors pass on pak loading.

ui/base/resource/resource_bundle_mac.mm

Index: ui/base/resource/resource_bundle_mac.mm
diff --git a/ui/base/resource/resource_bundle_mac.mm b/ui/base/resource/resource_bundle_mac.mm
index 2863e087d059aab8f11a7bd0440bd35ff551dac4..7a55aa6a1580e5fc2fbb220dd5b1746aa8c727ed 100644
--- a/ui/base/resource/resource_bundle_mac.mm
+++ b/ui/base/resource/resource_bundle_mac.mm
@@ -39,8 +39,14 @@ base::FilePath GetResourcesPakFilePath(NSString* name, NSString* mac_locale) {
   }
 
   if (!resource_path) {
-    // Return just the name of the pack file.
-    return base::FilePath(base::SysNSStringToUTF8(name) + ".pak");
+    // Trying to load a resources file that doesn't exist is an error. Return
+    // just the name of the pack file so that further down the line it is easier
+    // to track down what happened.
+    std::string name_string = base::SysNSStringToUTF8(name);
+    std::string locale_string = base::SysNSStringToUTF8(mac_locale);
+    LOG(ERROR) << "Tried to get the file path of a non-existent pak file '"
+               << name_string << "' for locale '" << locale_string << "'";
+    return base::FilePath(name_string + ".pak");
   }
 
   return base::FilePath([resource_path fileSystemRepresentation]);