Allow override of user agent depending on url.

content/public/renderer/render_frame_observer.cc

Index: content/public/renderer/render_frame_observer.cc
diff --git a/content/public/renderer/render_frame_observer.cc b/content/public/renderer/render_frame_observer.cc
index 19d77d01f0e0aeed354beff38cf40dbd708a1d6c..cace8256d48712c7451387843f97a6befc7232f2 100644
--- a/content/public/renderer/render_frame_observer.cc
+++ b/content/public/renderer/render_frame_observer.cc
@@ -33,6 +33,10 @@ void RenderFrameObserver::OnDestruct() {
   delete this;
 }
 
+std::string RenderFrameObserver::GetUserAgentOverrideForURL(const GURL& url) {
+  return "";

[jochen (gone - plz use gerrit), 2014/10/02 09:24:03]

nit std::string()

+}
+
 bool RenderFrameObserver::OnMessageReceived(const IPC::Message& message) {
   return false;
 }