[Extensions] Make chrome://extensions use developerPrivate for error calls

chrome/browser/extensions/api/developer_private/developer_private_api.h

Index: chrome/browser/extensions/api/developer_private/developer_private_api.h
diff --git a/chrome/browser/extensions/api/developer_private/developer_private_api.h b/chrome/browser/extensions/api/developer_private/developer_private_api.h
index cf95fc173ef04a1c3ce2345e026edda8ebd2388c..60edc0ce3ed328e7cf14d5221df7ff957d5c319c 100644
--- a/chrome/browser/extensions/api/developer_private/developer_private_api.h
+++ b/chrome/browser/extensions/api/developer_private/developer_private_api.h
@@ -47,6 +47,10 @@ struct ItemInfo;
 struct ItemInspectView;
 struct ProjectInfo;
 
+namespace RequestFileSource {
+struct Params;
+}
+
 }  // namespace developer_private
 
 }  // namespace api
@@ -443,36 +447,32 @@ class DeveloperPrivateLoadDirectoryFunction
 };
 
 class DeveloperPrivateRequestFileSourceFunction
-    : public ChromeAsyncExtensionFunction {
+    : public DeveloperPrivateAPIFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("developerPrivate.requestFileSource",
                              DEVELOPERPRIVATE_REQUESTFILESOURCE);
-
   DeveloperPrivateRequestFileSourceFunction();
 
  protected:
   ~DeveloperPrivateRequestFileSourceFunction() override;
-
-  // ExtensionFunction:
-  bool RunAsync() override;
+  ResponseAction Run() override;
 
  private:
-  void LaunchCallback(const base::DictionaryValue& results);
+  void Finish(const std::string& file_contents);
+
+  scoped_ptr<api::developer_private::RequestFileSource::Params> params_;
 };
 
 class DeveloperPrivateOpenDevToolsFunction
-    : public ChromeAsyncExtensionFunction {
+    : public DeveloperPrivateAPIFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("developerPrivate.openDevTools",
                              DEVELOPERPRIVATE_OPENDEVTOOLS);
-
   DeveloperPrivateOpenDevToolsFunction();
 
  protected:
   ~DeveloperPrivateOpenDevToolsFunction() override;
-
-  // ExtensionFunction:
-  bool RunAsync() override;
+  ResponseAction Run() override;
 };
 
 }  // namespace api