Avoid parsing the webstore base url so much.

chrome/browser/extensions/webstore_standalone_installer.cc

 // Copyright (c) 2012 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/webstore_standalone_installer.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
@@ skipping 280 matching lines @@
 
   // Icon URL is optional.
   GURL icon_url;
   if (webstore_data->HasKey(kIconUrlKey)) {
     std::string icon_url_string;
     if (!webstore_data->GetString(kIconUrlKey, &icon_url_string)) {
       CompleteInstall(webstore_install::INVALID_WEBSTORE_RESPONSE,
                       webstore_install::kInvalidWebstoreResponseError);
       return;
     }
-    icon_url = GURL(extension_urls::GetWebstoreLaunchURL()).Resolve(
-        icon_url_string);
+    icon_url = extension_urls::GetWebstoreLaunchURL().Resolve(icon_url_string);
     if (!icon_url.is_valid()) {
       CompleteInstall(webstore_install::INVALID_WEBSTORE_RESPONSE,
                       webstore_install::kInvalidWebstoreResponseError);
       return;
     }
   }
 
   // Assume ownership of webstore_data.
   webstore_data_ = std::move(webstore_data);
 
@@ skipping 97 matching lines @@
 void WebstoreStandaloneInstaller::OnWebStoreDataFetcherDone() {
   // An instance of this class is passed in as a delegate for the
   // WebstoreInstallHelper, ExtensionInstallPrompt and WebstoreInstaller, and
   // therefore needs to remain alive until they are done. Clear the webstore
   // data fetcher to avoid calling Release in AbortInstall while any of these
   // operations are in progress.
   webstore_data_fetcher_.reset();
 }
 
 }  // namespace extensions