Provide mutable members of UrlRequestContext via pure-virtual interface

net/url_request/url_request_context_builder.cc

Index: net/url_request/url_request_context_builder.cc
diff --git a/net/url_request/url_request_context_builder.cc b/net/url_request/url_request_context_builder.cc
index 3228bfbdf61ec66ec61c4a5b324aabadd7232a94..b5b6c8425d4aa1c097d2d020d49960e606bda003 100644
--- a/net/url_request/url_request_context_builder.cc
+++ b/net/url_request/url_request_context_builder.cc
@@ -9,6 +9,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "base/string_util.h"
 #include "base/threading/thread.h"
 #include "base/thread_task_runner_handle.h"
 #include "net/base/cert_verifier.h"
@@ -153,11 +154,6 @@ class BasicURLRequestContext : public URLRequestContext {
     return file_thread_.message_loop();
   }
 
-  virtual const std::string& GetUserAgent(
-      const GURL& /* url */) const OVERRIDE {
-    return user_agent_;
-  }
-
  protected:
   virtual ~BasicURLRequestContext() {}
 
@@ -208,7 +204,8 @@ URLRequestContext* URLRequestContextBuilder::Build() {
   BasicURLRequestContext* context = new BasicURLRequestContext;
   URLRequestContextStorage* storage = context->storage();
 
-  context->set_user_agent(user_agent_);
+  storage->set_http_user_agent_settings(new ConstHttpUserAgentSettings(
+    EmptyString(), EmptyString(), user_agent_));
 
   BasicNetworkDelegate* network_delegate = new BasicNetworkDelegate;
   storage->set_network_delegate(network_delegate);