Make WebTaskRunner ThreadSafeRefCounted

third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h

Index: third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h
diff --git a/third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h b/third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h
index 64f4f30fab9fcbf4a9c7c2146c9f2397f67831a6..c8bd52f3a0e24e305f1d5bdca9454c46f1828dd0 100644
--- a/third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h
+++ b/third_party/WebKit/Source/core/workers/ParentFrameTaskRunners.h
@@ -38,13 +38,15 @@ class CORE_EXPORT ParentFrameTaskRunners final
   }
 
   // Might return nullptr for unsupported task types.
-  WebTaskRunner* get(TaskType);
+  RefPtr<WebTaskRunner> get(TaskType);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
-  using TaskRunnerHashMap =
-      HashMap<TaskType, WebTaskRunner*, WTF::IntHash<TaskType>, TaskTypeTraits>;
+  using TaskRunnerHashMap = HashMap<TaskType,
+                                    RefPtr<WebTaskRunner>,
+                                    WTF::IntHash<TaskType>,
+                                    TaskTypeTraits>;
 
   // LocalFrame could be nullptr if the worker is not associated with a
   // particular local frame.