Added enhanced bookmarks extension as an external component extension

chrome/browser/extensions/external_component_loader.cc

 // Copyright (c) 2013 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/extensions/external_component_loader.h"
 
+#include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "base/values.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_constants.h"
+#include "components/variations/variations_associated_data.h"
+#include "extensions/common/features/feature.h"
+#include "extensions/common/features/feature_provider.h"
 
 namespace extensions {
 
+const char kFieldTrialName[] = "EnhancedBookmarks";
+
 ExternalComponentLoader::ExternalComponentLoader() {}
 
 ExternalComponentLoader::~ExternalComponentLoader() {}
 
+// This function will be removed after experiment goes to all users or go away.
+bool ExternalComponentLoader::IsEnhancedBookmarksExperimentEnabled() {
+  const char kFieldTrialDefaultGroupName[] = "Default";
+  std::string field_trial_group_name =
+      base::FieldTrialList::FindFullName(kFieldTrialName);
+  if (field_trial_group_name.empty() ||
+      field_trial_group_name == kFieldTrialDefaultGroupName) {
+    return false;
+  }
+  std::string app_id =
+      chrome_variations::GetVariationParamValue(kFieldTrialName, "id");
+  FeatureProvider* feature_provider = FeatureProvider::GetPermissionFeatures();
+  Feature* feature = feature_provider->GetFeature("metricsPrivate");
+  return (feature && feature->IsIdInWhitelist(app_id));
+}
+
 void ExternalComponentLoader::StartLoading() {
   prefs_.reset(new base::DictionaryValue());
   std::string appId = extension_misc::kInAppPaymentsSupportAppId;
   prefs_->SetString(appId + ".external_update_url",
                     extension_urls::GetWebstoreUpdateUrl().spec());
+
+  if (IsEnhancedBookmarksExperimentEnabled() &&
+      (CommandLine::ForCurrentProcess()->
+          GetSwitchValueASCII(switches::kEnableEnhancedBookmarks) != "0")) {
+    std::string app_id =
+        chrome_variations::GetVariationParamValue(kFieldTrialName, "id");
+    prefs_->SetString(app_id + ".external_update_url",

[meacer, 2013/11/26 01:32:03]

Can we restrict the update url to Web Store for all external components in
addition to this? Since now external components aren't going to be listed in the
extensions page, it would be good if we can make sure they are only updated
through the Web Store, as a hardening mechanism.

+                      extension_urls::GetWebstoreUpdateUrl().spec());
+  }
   LoadFinished();
 }
 
 }  // namespace extensions