Prefetching: Introduce store commands abstractions to be used by tasks.

components/offline_pages/core/prefetch/add_unique_urls_task.cc

Index: components/offline_pages/core/prefetch/add_unique_urls_task.cc
diff --git a/components/offline_pages/core/prefetch/add_unique_urls_task.cc b/components/offline_pages/core/prefetch/add_unique_urls_task.cc
index 58f46a0ed03a00df250c1276d8ed5439ac2aeef2..e25cc54a9bccf404e2d713a7de3dc98b4638e3a4 100644
--- a/components/offline_pages/core/prefetch/add_unique_urls_task.cc
+++ b/components/offline_pages/core/prefetch/add_unique_urls_task.cc
@@ -4,21 +4,55 @@
 
 #include "components/offline_pages/core/prefetch/add_unique_urls_task.h"
 
+#include <memory>
+#include <utility>
+
 #include "base/bind.h"
+#include "base/callback.h"
+#include "url/gurl.h"
 
 namespace offline_pages {
 
+namespace {
+
+// Adds new prefetch item entries to the store using the URLs and client IDs
+// from |prefetch_urls| and the client's |name_space|. Also cleans up entries in
+// the Zombie state from the client's |name_space| except for the ones
+// whose URL is contained in |prefetch_urls|.
+// Returns the number of added prefecth items.
+static int AddUrlsAndCleanupZombies(
+    const std::string& name_space,
+    const std::vector<PrefetchURL>& prefetch_urls) {
+  NOTIMPLEMENTED();
+  return 1;
+}
+
+// TODO(fgorski): replace this with the SQL executor.
+static void Execute(base::RepeatingCallback<int()> command_callback,
+                    base::OnceCallback<void(int)> result_callback) {
+  std::move(result_callback).Run(command_callback.Run());
+}
+}
+
 AddUniqueUrlsTask::AddUniqueUrlsTask(
-    PrefetchStore* store,
+    const std::string& name_space,
     const std::vector<PrefetchURL>& prefetch_urls)
-    : prefetch_store_(store),
+    : name_space_(name_space),
       prefetch_urls_(prefetch_urls),
       weak_ptr_factory_(this) {}
 
 AddUniqueUrlsTask::~AddUniqueUrlsTask() {}
 
 void AddUniqueUrlsTask::Run() {
-  CHECK(prefetch_store_);
+  Execute(base::BindRepeating(&AddUrlsAndCleanupZombies, name_space_,
+                              prefetch_urls_),
+          base::BindOnce(&AddUniqueUrlsTask::OnUrlsAdded,
+                         weak_ptr_factory_.GetWeakPtr()));
+}
+
+void AddUniqueUrlsTask::OnUrlsAdded(int added_entry_count) {
+  // TODO(carlosk): schedule NWake here if at least one new entry was added to
+  // the store.
   TaskComplete();
 }