Make URLRequestThrottlerManager a member of URLRequestContext.

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 5f217d69ea86b7fb7dd40f30ab99c2e983f01a7f..46a2a9bfdb61b3e298ab9dfc40aae5fef15b8f20 100644
--- a/net/url_request/url_request_context_builder.cc
+++ b/net/url_request/url_request_context_builder.cc
@@ -26,6 +26,7 @@
 #include "net/proxy/proxy_service.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_storage.h"
+#include "net/url_request/url_request_throttler_manager.h"
 
 namespace net {
 
@@ -217,6 +218,7 @@ scoped_refptr<URLRequestContext> URLRequestContextBuilder::Build() {
   storage->set_transport_security_state(new net::TransportSecurityState(""));
   storage->set_http_server_properties(new net::HttpServerPropertiesImpl);
   storage->set_cert_verifier(CertVerifier::CreateDefault());
+  storage->set_throttler_manager(new URLRequestThrottlerManager());
 
   HttpTransactionFactory* http_transaction_factory = NULL;
   if (http_cache_enabled_) {