[Extensions] Convert some ChromeSyncExtensionFunctions

extensions/browser/extension_function.cc

 // Copyright 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 "extensions/browser/extension_function.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 207 matching lines @@
   --count_;
 }
 
 
 }  // namespace
 
 // static
 bool ExtensionFunction::ignore_all_did_respond_for_testing_do_not_use = false;
 
 // static
+const char* ExtensionFunction::kUnknownErrorDoNotUse = "Unknown error.";
+
+// static
 void ExtensionFunctionDeleteTraits::Destruct(const ExtensionFunction* x) {
   x->Destruct();
 }
 
 // Helper class to track the lifetime of ExtensionFunction's RenderFrameHost and
 // notify the function when it is deleted, as well as forwarding any messages
 // to the ExtensionFunction.
 class UIThreadExtensionFunction::RenderFrameHostTracker
     : public content::WebContentsObserver {
  public:
@@ skipping 375 matching lines @@
 
 ExtensionFunction::ResponseAction AsyncExtensionFunction::Run() {
   return RunAsync() ? RespondLater() : RespondNow(Error(error_));
 }
 
 // static
 bool AsyncExtensionFunction::ValidationFailure(
     AsyncExtensionFunction* function) {
   return false;
 }