Make UTF16ToASCII and UTF16TOUTF8 take a StringPiece

android_webview/renderer/aw_content_renderer_client.cc

Index: android_webview/renderer/aw_content_renderer_client.cc
diff --git a/android_webview/renderer/aw_content_renderer_client.cc b/android_webview/renderer/aw_content_renderer_client.cc
index 79c33cf75ec4f55ae29ed85a7fae44d927eaf872..f1ccc5d9331defe26d68da50811dd0cb2dd8f83e 100644
--- a/android_webview/renderer/aw_content_renderer_client.cc
+++ b/android_webview/renderer/aw_content_renderer_client.cc
@@ -111,7 +111,8 @@ void AwContentRendererClient::GetNavigationErrorStrings(
     base::string16* error_description) {
   if (error_html) {
     GURL error_url(failed_request.url());
-    std::string err = base::UTF16ToUTF8(error.localizedDescription);
+    std::string err =
+        base::UTF16ToUTF8(base::StringPiece16(error.localizedDescription));
     std::string contents;
     if (err.empty()) {
       contents = AwResource::GetNoDomainPageContent();