Refactor extension event distribution to use Values instead of JSON strings.

chrome/browser/extensions/extension_preference_helpers.cc

Index: chrome/browser/extensions/extension_preference_helpers.cc
diff --git a/chrome/browser/extensions/extension_preference_helpers.cc b/chrome/browser/extensions/extension_preference_helpers.cc
index 1652c8a3a64b7d401c1b66c0bc48886b3efa3f0c..5b32c6313516af981362535c5f5b8224f4291871 100644
--- a/chrome/browser/extensions/extension_preference_helpers.cc
+++ b/chrome/browser/extensions/extension_preference_helpers.cc
@@ -101,8 +101,6 @@ void DispatchEventToExtensions(
       std::string level_of_control =
           GetLevelOfControl(profile, extension_id, browser_pref, incognito);
       dict->SetString(kLevelOfControlKey, level_of_control);
-      std::string json_args;
-      base::JSONWriter::Write(args, &json_args);
 
       // If the extension is in incognito split mode,
       // a) incognito pref changes are visible only to the incognito tabs
@@ -124,7 +122,7 @@ void DispatchEventToExtensions(
       }
 
       router->DispatchEventToExtension(
-          extension_id, event_name, json_args, restrict_to_profile, GURL());
+          extension_id, event_name, args, restrict_to_profile, GURL());
     }
   }
 }