Add a pref name for share targets, and store their manifest data.

chrome/browser/webshare/share_target_pref_helper.cc

Index: chrome/browser/webshare/share_target_pref_helper.cc
diff --git a/chrome/browser/webshare/share_target_pref_helper.cc b/chrome/browser/webshare/share_target_pref_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f09fc14ab79277635acfd30fab4a59316e6fe453
--- /dev/null
+++ b/chrome/browser/webshare/share_target_pref_helper.cc
@@ -0,0 +1,32 @@
+// Copyright 2017 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 "chrome/browser/webshare/share_target_pref_helper.h"
+
+#include "base/values.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/scoped_user_pref_update.h"
+
+void UpdateShareTargetInPrefs(base::StringPiece manifest_url,
+                              base::Optional<std::string> url_template,
+                              PrefService* pref_service) {
+  DictionaryPrefUpdate update(pref_service, prefs::kWebShareVisitedTargets);
+  base::DictionaryValue* share_target_dict = update.Get();
+
+  if (!url_template.has_value()) {
+    share_target_dict->RemoveWithoutPathExpansion(manifest_url, NULL);
+    return;
+  }
+
+  constexpr char kUrlTemplateKey[] = "url_template";
+
+  std::unique_ptr<base::DictionaryValue> origin_dict(new base::DictionaryValue);
+
+  origin_dict->SetStringWithoutPathExpansion(kUrlTemplateKey,
+                                             url_template.value());
+
+  share_target_dict->SetWithoutPathExpansion(manifest_url,
+                                             std::move(origin_dict));
+}