Expose GetLoggingFileName in ContentBrowserClient.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 7f00fb51046525198fe4a6d4458f08e508718458..9e0a5b49faa95934fb4b98cfeae03fed7f955824 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -151,6 +151,10 @@ const gfx::ImageSkia* ContentBrowserClient::GetDefaultFavicon() {
   return empty;
 }
 
+base::FilePath ContentBrowserClient::GetLoggingFileName() {
+  return base::FilePath();
+}
+
 bool ContentBrowserClient::AllowAppCache(const GURL& manifest_url,
                                          const GURL& first_party,
                                          ResourceContext* context) {