Remove unused function on HTMLImportsController.

Source/core/html/imports/HTMLImportsController.cpp

Index: Source/core/html/imports/HTMLImportsController.cpp
diff --git a/Source/core/html/imports/HTMLImportsController.cpp b/Source/core/html/imports/HTMLImportsController.cpp
index 1a345c33548438f2bc891740f4051cb9e5d61576..1b7915ad63d99b58237830f031244022e53ce4b5 100644
--- a/Source/core/html/imports/HTMLImportsController.cpp
+++ b/Source/core/html/imports/HTMLImportsController.cpp
@@ -124,11 +124,6 @@ HTMLImportChild* HTMLImportsController::load(HTMLImport* parent, HTMLImportChild
     return child;
 }
 
-void HTMLImportsController::showSecurityErrorMessage(const String& message)
-{
-    master()->addConsoleMessage(JSMessageSource, ErrorMessageLevel, message);
-}
-
 Document* HTMLImportsController::master() const
 {
     return root()->document();