Add a DistilledContentStore (and an in-memory impl)

components/dom_distiller/core/distilled_content_store.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/dom_distiller/core/distilled_content_store.h"
+
+#include "base/message_loop/message_loop.h"
+
+namespace dom_distiller {
+
+InMemoryContentStore::InMemoryContentStore() {}
+InMemoryContentStore::~InMemoryContentStore() {}
+
+void InMemoryContentStore::SaveContent(
+    const ArticleEntry& entry,
+    const DistilledArticleProto& proto,
+    InMemoryContentStore::SaveCallback callback) {
+  InjectContent(entry, proto);
+  if (!callback.is_null()) {
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(callback, true));
+  }
+}
+
+void InMemoryContentStore::LoadContent(
+    const ArticleEntry& entry,
+    InMemoryContentStore::LoadCallback callback) const {
+  if (callback.is_null())
+    return;
+
+  ContentMap::const_iterator it = cache_.find(entry.entry_id());
+  bool success = it != cache_.end();
+  scoped_ptr<DistilledArticleProto> distilled_article;
+  if (success) {
+    distilled_article.reset(new DistilledArticleProto(it->second));
+  } else {
+    distilled_article.reset(new DistilledArticleProto());
+  }
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, success, base::Passed(&distilled_article)));
+}
+
+void InMemoryContentStore::InjectContent(const ArticleEntry& entry,
+                                         const DistilledArticleProto& proto) {
+  cache_[entry.entry_id()] = proto;
+}
+
+}  // namespace dom_distiller