[extensions] Stop parsing webstore urls so much

extensions/shell/common/shell_extensions_client.cc

Index: extensions/shell/common/shell_extensions_client.cc
diff --git a/extensions/shell/common/shell_extensions_client.cc b/extensions/shell/common/shell_extensions_client.cc
index 0e87dae087b9a46890ab0e05a303e74bfd0a2f99..0d2557a75ad8e28f050c6c66f863fd605f6b10dd 100644
--- a/extensions/shell/common/shell_extensions_client.cc
+++ b/extensions/shell/common/shell_extensions_client.cc
@@ -76,8 +76,8 @@ base::LazyInstance<ShellPermissionMessageProvider>
 }  // namespace
 
 ShellExtensionsClient::ShellExtensionsClient()
-    : extensions_api_permissions_(ExtensionsAPIPermissions()) {
-}
+    : extensions_api_permissions_(ExtensionsAPIPermissions()),
+      webstore_update_url_(extension_urls::kChromeWebstoreUpdateURL) {}
 
 ShellExtensionsClient::~ShellExtensionsClient() {
 }
@@ -185,8 +185,8 @@ std::string ShellExtensionsClient::GetWebstoreBaseURL() const {
   return extension_urls::kChromeWebstoreBaseURL;
 }
 
-std::string ShellExtensionsClient::GetWebstoreUpdateURL() const {
-  return extension_urls::kChromeWebstoreUpdateURL;
+const GURL& ShellExtensionsClient::GetWebstoreUpdateURL() const {
+  return webstore_update_url_;
 }
 
 bool ShellExtensionsClient::IsBlacklistUpdateURL(const GURL& url) const {