[NTP Snippets] Persist the set of snippets in a pref

components/ntp_snippets/ntp_snippet.cc

 // Copyright 2015 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/ntp_snippets/ntp_snippet.h"
+
 #include "base/values.h"
 
+namespace {
+
+const char kUrl[] = "url";
+const char kSiteTitle[] = "site_title";
+const char kTitle[] = "title";
+const char kFaviconUrl[] = "favicon_url";
+const char kSalientImageUrl[] = "thumbnailUrl";
+const char kSnippet[] = "snippet";
+const char kPublishDate[] = "creationTimestampSec";
+const char kExpiryDate[] = "expiryTimestampSec";
+
+}  // namespace
+
 namespace ntp_snippets {
 
 NTPSnippet::NTPSnippet(const GURL& url) : url_(url) {
-  DCHECK(url_.is_valid() && !url.is_empty());
+  DCHECK(url_.is_valid());
 }
 
 NTPSnippet::~NTPSnippet() {}
 
 // static
-scoped_ptr<NTPSnippet> NTPSnippet::NTPSnippetFromDictionary(
+scoped_ptr<NTPSnippet> NTPSnippet::CreateFromDictionary(
     const base::DictionaryValue& dict) {
   // Need at least the url.
   std::string url;
   if (!dict.GetString("url", &url))
     return nullptr;
 
+  // TODO(treib,noyau): Need to check that the URL is valid first, or remove
+  // the DCHECK in the constructor.
   scoped_ptr<NTPSnippet> snippet(new NTPSnippet(GURL(url)));
 
   std::string site_title;
-  if (dict.GetString("site_title", &site_title))
+  if (dict.GetString(kSiteTitle, &site_title))
     snippet->set_site_title(site_title);
+  std::string title;
+  if (dict.GetString(kTitle, &title))
+    snippet->set_title(title);
   std::string favicon_url;
-  if (dict.GetString("favicon_url", &favicon_url))
+  if (dict.GetString(kFaviconUrl, &favicon_url))
     snippet->set_favicon_url(GURL(favicon_url));
-  std::string title;
-  if (dict.GetString("title", &title))
-    snippet->set_title(title);
+  std::string salient_image_url;
+  if (dict.GetString(kSalientImageUrl, &salient_image_url))
+    snippet->set_salient_image_url(GURL(salient_image_url));
   std::string snippet_str;
-  if (dict.GetString("snippet", &snippet_str))
+  if (dict.GetString(kSnippet, &snippet_str))
     snippet->set_snippet(snippet_str);
-  std::string salient_image_url;
-  if (dict.GetString("thumbnailUrl", &salient_image_url))
-    snippet->set_salient_image_url(GURL(salient_image_url));
   int creation_timestamp;
-  if (dict.GetInteger("creationTimestampSec", &creation_timestamp)) {
+  if (dict.GetInteger(kPublishDate, &creation_timestamp)) {
     snippet->set_publish_date(base::Time::UnixEpoch() +
                               base::TimeDelta::FromSeconds(creation_timestamp));
   }
   // TODO: Dates in json?
 
   return snippet;
 }
 
+scoped_ptr<base::DictionaryValue> NTPSnippet::ToDictionary() const {
+  scoped_ptr<base::DictionaryValue> dict(new base::DictionaryValue);
+
+  dict->SetString(kUrl, url_.spec());
+  if (!site_title_.empty())
+    dict->SetString(kSiteTitle, site_title_);
+  if (!title_.empty())
+    dict->SetString(kTitle, title_);
+  if (favicon_url_.is_valid())
+    dict->SetString(kFaviconUrl, favicon_url_.spec());
+  if (salient_image_url_.is_valid())
+    dict->SetString(kSalientImageUrl, salient_image_url_.spec());
+  if (!snippet_.empty())
+    dict->SetString(kSnippet, snippet_);
+  if (!publish_date_.is_null()) {
+    dict->SetInteger(kPublishDate,
+                     (publish_date_ - base::Time::UnixEpoch()).InSeconds());
+  }
+  if (!expiry_date_.is_null()) {
+    dict->SetInteger(kExpiryDate,
+                     (expiry_date_ - base::Time::UnixEpoch()).InSeconds());
+  }
+
+  return dict;
+}
+
 }  // namespace ntp_snippets