Revert of Server push cancellation: add a finch trial parameter

net/http/http_cache.cc

Index: net/http/http_cache.cc
diff --git a/net/http/http_cache.cc b/net/http/http_cache.cc
index 904797a1a589eeebf1643abce6c773b8218e3603..1dc390a474c3abcc21e95539ed56ef75fb9dda16 100644
--- a/net/http/http_cache.cc
+++ b/net/http/http_cache.cc
@@ -38,7 +38,6 @@
 #include "net/base/upload_data_stream.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/http/disk_cache_based_quic_server_info.h"
-#include "net/http/http_cache_lookup_manager.h"
 #include "net/http/http_cache_transaction.h"
 #include "net/http/http_network_layer.h"
 #include "net/http/http_network_session.h"
@@ -344,20 +343,14 @@
   // Session may be NULL in unittests.
   // TODO(mmenke): Seems like tests could be changed to provide a session,
   // rather than having logic only used in unit tests here.
-  if (!session)
-    return;
-
-  net_log_ = session->net_log();
-  if (!is_main_cache)
-    return;
-
-  session->SetServerPushDelegate(
-      base::MakeUnique<HttpCacheLookupManager>(this));
-
-  if (!session->quic_stream_factory()->has_quic_server_info_factory()) {
-    // QuicStreamFactory takes ownership of QuicServerInfoFactoryAdaptor.
-    session->quic_stream_factory()->set_quic_server_info_factory(
-        new QuicServerInfoFactoryAdaptor(this));
+  if (session) {
+    net_log_ = session->net_log();
+    if (is_main_cache &&
+        !session->quic_stream_factory()->has_quic_server_info_factory()) {
+      // QuicStreamFactory takes ownership of QuicServerInfoFactoryAdaptor.
+      session->quic_stream_factory()->set_quic_server_info_factory(
+          new QuicServerInfoFactoryAdaptor(this));
+    }
   }
 }