base: Remove 'using' declaration of StringAppendV.

chrome/common/extensions/update_manifest.cc

Index: chrome/common/extensions/update_manifest.cc
diff --git a/chrome/common/extensions/update_manifest.cc b/chrome/common/extensions/update_manifest.cc
index 3329456715606e949e2619060b6369d4e775cfe7..c6e8788b82d12a33abf834917eff33783d66b067 100644
--- a/chrome/common/extensions/update_manifest.cc
+++ b/chrome/common/extensions/update_manifest.cc
@@ -35,7 +35,7 @@ void UpdateManifest::ParseError(const char* details, ...) {
     // TODO(asargent) make a platform abstracted newline?
     errors_ += "\r\n";
   }
-  StringAppendV(&errors_, details, args);
+  base::StringAppendV(&errors_, details, args);
   va_end(args);
 }
 
@@ -81,7 +81,7 @@ static void XmlErrorFunc(void *context, const char *message, ...) {
   va_list args;
   va_start(args, message);
   std::string* error = static_cast<std::string*>(context);
-  StringAppendV(error, message, args);
+  base::StringAppendV(error, message, args);
   va_end(args);
 }