Add a missing handle scope to ScriptController::shouldBypassMainWorldCSP

Although I cannot reproduce the crash, as far as I see the crash report,
it seems that we are missing a handle scope in ScriptController::shouldBypassMainWorldCSP.

BUG=411773
TEST=None, I cannot reproduce

Review URL: https://codereview.chromium.org/556713002

git-svn-id: svn://svn.chromium.org/blink/trunk@181647 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/bindings/core/v8/ScriptController.cpp

@@ -243,6 +243,7 @@ WindowProxy* ScriptController::windowProxy(DOMWrapperWorld& world)
 
 bool ScriptController::shouldBypassMainWorldCSP()
 {
+    v8::HandleScope handleScope(m_isolate);
     v8::Handle<v8::Context> context = m_isolate->GetCurrentContext();
     if (context.IsEmpty() || !toDOMWindow(context))
         return false;