Mojo C++ bindings: switch WebKit mojom targets to use STL/WTF types.

content/browser/mime_registry_impl.cc

Index: content/browser/mime_registry_impl.cc
diff --git a/content/browser/mime_registry_impl.cc b/content/browser/mime_registry_impl.cc
index 156551d7e6f74ee559302a95d6fb1a6c3609de85..e65c19997be513c1059c14faf9b800a9fd694643 100644
--- a/content/browser/mime_registry_impl.cc
+++ b/content/browser/mime_registry_impl.cc
@@ -24,12 +24,12 @@ void MimeRegistryImpl::Create(blink::mojom::MimeRegistryRequest request) {
 }
 
 void MimeRegistryImpl::GetMimeTypeFromExtension(
-    const mojo::String& extension,
+    const std::string& extension,
     const GetMimeTypeFromExtensionCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   std::string mime_type;
-  net::GetMimeTypeFromExtension(extension.To<base::FilePath::StringType>(),
-                                &mime_type);
+  net::GetMimeTypeFromExtension(
+      mojo::String(extension).To<base::FilePath::StringType>(), &mime_type);
   callback.Run(mime_type);
 }