[Blimp] Adds Blimp EngineSession and ClientSession skeleton

blimp/engine/browser/blimp_url_request_context_getter.cc

Index: blimp/engine/browser/blimp_url_request_context_getter.cc
diff --git a/blimp/engine/browser/blimp_url_request_context_getter.cc b/blimp/engine/browser/blimp_url_request_context_getter.cc
index e49c5f25416fe9018c0a3656d6307647fa6ada82..f2bc1dec1a4a03c2688a76932f3012b56e5220bc 100644
--- a/blimp/engine/browser/blimp_url_request_context_getter.cc
+++ b/blimp/engine/browser/blimp_url_request_context_getter.cc
@@ -180,10 +180,10 @@ net::URLRequestContext* BlimpURLRequestContextGetter::GetURLRequestContext() {
     network_session_params.host_resolver =
         url_request_context_->host_resolver();
 
-    storage_->set_http_transaction_factory(
-        make_scoped_ptr(
-            new net::HttpCache(network_session_params, main_backend))
-            .Pass());
+    storage_->set_http_network_session(
+        make_scoped_ptr(new net::HttpNetworkSession(network_session_params)));
+    storage_->set_http_transaction_factory(make_scoped_ptr(new net::HttpCache(
+        storage_->http_network_session(), main_backend, true)));
 
     scoped_ptr<net::URLRequestJobFactoryImpl> job_factory(
         new net::URLRequestJobFactoryImpl());