Allow component installers to specify a map of installer attributes.

chrome/browser/component_updater/supervised_user_whitelist_installer.cc

Index: chrome/browser/component_updater/supervised_user_whitelist_installer.cc
diff --git a/chrome/browser/component_updater/supervised_user_whitelist_installer.cc b/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
index 97f9db07e04327ce7c5cf95da638f32d71156bf7..c903f115d864c601478fa4846e1a092c30dd4588 100644
--- a/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
+++ b/chrome/browser/component_updater/supervised_user_whitelist_installer.cc
@@ -260,7 +260,7 @@ class SupervisedUserWhitelistComponentInstallerTraits
   base::FilePath GetRelativeInstallDir() const override;
   void GetHash(std::vector<uint8_t>* hash) const override;
   std::string GetName() const override;
-  std::string GetAp() const override;
+  update_client::InstallerAttributes GetInstallerAttributes() const override;
 
   std::string crx_id_;
   std::string name_;
@@ -320,8 +320,10 @@ std::string SupervisedUserWhitelistComponentInstallerTraits::GetName() const {
   return name_;
 }
 
-std::string SupervisedUserWhitelistComponentInstallerTraits::GetAp() const {
-  return std::string();
+update_client::InstallerAttributes
+SupervisedUserWhitelistComponentInstallerTraits::GetInstallerAttributes()
+    const {
+  return update_client::InstallerAttributes();
 }
 
 class SupervisedUserWhitelistInstallerImpl