Create skeleton for the Prefetching store and initial pipeline step.

components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h

Index: components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h
diff --git a/components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h b/components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h
index e826d0a9f9ce4b4996f53f5c6e940f6150a85618..0f810567027dc37abe33a02b6d539b20b7885bb1 100644
--- a/components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h
+++ b/components/offline_pages/core/prefetch/prefetch_dispatcher_impl.h
@@ -5,25 +5,36 @@
 #ifndef COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_DISPATCHER_IMPL_H_
 #define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_DISPATCHER_IMPL_H_
 
+#include <memory>
+
 #include "base/macros.h"
 #include "components/offline_pages/core/prefetch/prefetch_dispatcher.h"
+#include "components/offline_pages/core/prefetch/prefetch_store.h"
+#include "components/offline_pages/core/task_queue.h"
 
 namespace offline_pages {
 
 class PrefetchDispatcherImpl : public PrefetchDispatcher {
  public:
-  PrefetchDispatcherImpl();
+  PrefetchDispatcherImpl(std::unique_ptr<PrefetchStore> store);
   ~PrefetchDispatcherImpl() override;
 
   // PrefetchDispatcher implementation:
   void AddCandidatePrefetchURLs(
-      const std::vector<PrefetchURL>& suggested_urls) override;
+      const std::string& name_space,
+      const std::vector<PrefetchURL>& prefetch_urls) override;
   void RemoveAllUnprocessedPrefetchURLs(const std::string& name_space) override;
-  void RemovePrefetchURLsByClientId(const ClientId& client_id) override;
+  void RemovePrefetchURLsByClientId(const std::string& name_space,
+                                    const std::string& client_id) override;
   void BeginBackgroundTask(std::unique_ptr<ScopedBackgroundTask> task) override;
   void StopBackgroundTask(ScopedBackgroundTask* task) override;
 
  private:
+  friend class PrefetchDispatcherTest;
+
+  std::unique_ptr<PrefetchStore> store_;

[Dmitry Titov, 2017/05/18 21:24:02]

Should these rather live on PrefetchService and be injected in its constructor?
The PrefetchDispatcher may just keep a pointer back to PrefetchService to
retrieve other subcomponents.

Sooner or later it will have such a pointer and will pull other subcomponents
form the Service, so it might be good to just adopt this pattern now.

[carlosk, 2017/05/24 20:57:26]

Done.

+  TaskQueue task_queue_;
+
   DISALLOW_COPY_AND_ASSIGN(PrefetchDispatcherImpl);
 };