Avoid parsing the webstore base url so much.

extensions/shell/common/shell_extensions_client.h

 // Copyright 2014 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.
 
 #ifndef EXTENSIONS_SHELL_COMMON_SHELL_EXTENSIONS_CLIENT_H_
 #define EXTENSIONS_SHELL_COMMON_SHELL_EXTENSIONS_CLIENT_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "extensions/common/extensions_client.h"
@@ skipping 23 matching lines @@
   void SetScriptingWhitelist(const ScriptingWhitelist& whitelist) override;
   const ScriptingWhitelist& GetScriptingWhitelist() const override;
   URLPatternSet GetPermittedChromeSchemeHosts(
       const Extension* extension,
       const APIPermissionSet& api_permissions) const override;
   bool IsScriptableURL(const GURL& url, std::string* error) const override;
   bool IsAPISchemaGenerated(const std::string& name) const override;
   base::StringPiece GetAPISchema(const std::string& name) const override;
   bool ShouldSuppressFatalErrors() const override;
   void RecordDidSuppressFatalError() override;
-  std::string GetWebstoreBaseURL() const override;
+  const GURL& GetWebstoreBaseURL() const override;
   const GURL& GetWebstoreUpdateURL() const override;
   bool IsBlacklistUpdateURL(const GURL& url) const override;
 
  private:
   const ExtensionsAPIPermissions extensions_api_permissions_;
 
   ScriptingWhitelist scripting_whitelist_;
 
+  const GURL webstore_base_url_;
   const GURL webstore_update_url_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellExtensionsClient);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_SHELL_COMMON_SHELL_EXTENSIONS_CLIENT_H_