Add TaskRunnerHelper::get for Frame that casts to LocalFrame if possible or uses nullptr.

third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp

Index: third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
diff --git a/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp b/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
index c7f578b378db1da39959338cce06ad95dc3d395a..2434d41f45da19d66acd5b8774862f91e27275c7 100644
--- a/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
+++ b/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
@@ -48,6 +48,10 @@ RefPtr<WebTaskRunner> TaskRunnerHelper::get(TaskType type, LocalFrame* frame) {
   return nullptr;
 }
 
+RefPtr<WebTaskRunner> TaskRunnerHelper::get(TaskType type, Frame* frame) {
+  return get(type, frame->isLocalFrame() ? toLocalFrame(frame) : nullptr);
+}
+
 RefPtr<WebTaskRunner> TaskRunnerHelper::get(TaskType type, Document* document) {
   return get(type, document ? document->frame() : nullptr);
 }