Change the first parameter of savePage.saveAsMHTML to be a dictionary.

chrome/browser/extensions/extension_save_page_api.cc

Index: chrome/browser/extensions/extension_save_page_api.cc
diff --git a/chrome/browser/extensions/extension_save_page_api.cc b/chrome/browser/extensions/extension_save_page_api.cc
index 2a934b2b73924af140285b7f9d857d5dc6f3d111..97f52707430e9898d00ee3844a5308e636c15a07 100644
--- a/chrome/browser/extensions/extension_save_page_api.cc
+++ b/chrome/browser/extensions/extension_save_page_api.cc
@@ -33,7 +33,13 @@ SavePageAsMHTMLFunction::~SavePageAsMHTMLFunction() {
 }
 
 bool SavePageAsMHTMLFunction::RunImpl() {
-  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &tab_id_));
+  DictionaryValue* args;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(0, &args));
+
+  if (!args->HasKey("tabId"))
+    return false;
+
+  EXTENSION_FUNCTION_VALIDATE(args->GetInteger("tabId", &tab_id_));
 
   AddRef();  // Balanced in ReturnFailure/ReturnSuccess()