Create skeleton for the Prefetching store and initial pipeline step.

chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc

Index: chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc
diff --git a/chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc b/chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc
index 94a3a027aa280d22661c55df8d082e858a2f6ac6..b4d30fedf138d08b85ed1ca2d0eaf7b071b52eca 100644
--- a/chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc
+++ b/chrome/browser/offline_pages/prefetch/prefetch_service_factory.cc
@@ -4,11 +4,15 @@
 
 #include "chrome/browser/offline_pages/prefetch/prefetch_service_factory.h"
 
+#include <memory>
+
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/offline_pages/prefetch/offline_metrics_collector_impl.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h"
 #include "components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h"
+#include "components/offline_pages/core/prefetch/prefetch_in_memory_store.h"
 #include "components/offline_pages/core/prefetch/prefetch_service_impl.h"
 #include "content/public/browser/browser_context.h"
 
@@ -32,12 +36,15 @@ PrefetchService* PrefetchServiceFactory::GetForBrowserContext(
 
 KeyedService* PrefetchServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
-  auto prefetch_gcm_app_handler = base::MakeUnique<PrefetchGCMAppHandler>();
+  auto dispatcher_impl = base::MakeUnique<PrefetchDispatcherImpl>();
   auto offline_metrics_collector =
       base::MakeUnique<OfflineMetricsCollectorImpl>();
+  auto gcm_handler = base::MakeUnique<PrefetchGCMAppHandler>();
+  auto in_memory_store = base::MakeUnique<PrefetchInMemoryStore>();
 
-  return new PrefetchServiceImpl(std::move(prefetch_gcm_app_handler),
-                                 std::move(offline_metrics_collector));
+  return new PrefetchServiceImpl(
+      std::move(offline_metrics_collector), std::move(dispatcher_impl),
+      std::move(gcm_handler), std::move(in_memory_store));
 }
 
 }  // namespace offline_pages