diff --git a/third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h b/third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h
index f96565d805cb..2e16aa27c84d 100644
--- a/third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h
+++ b/third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h
@@ -31,10 +31,10 @@ class CORE_EXPORT ScriptedIdleTaskController
   static ScriptedIdleTaskController* Create(ExecutionContext* context) {
     return new ScriptedIdleTaskController(context);
   }
-  ~ScriptedIdleTaskController();
+  ~ScriptedIdleTaskController() override;

-  void Trace(blink::Visitor*);
-  void TraceWrappers(const ScriptWrappableVisitor*) const;
+  void Trace(blink::Visitor*) override;
+  void TraceWrappers(const ScriptWrappableVisitor*) const override;

   using CallbackId = int;

@@ -44,7 +44,7 @@ class CORE_EXPORT ScriptedIdleTaskController
                    public TraceWrapperBase {
    public:
     virtual void Trace(blink::Visitor* visitor) {}
-    virtual void TraceWrappers(const ScriptWrappableVisitor* visitor) const {}
+    virtual void TraceWrappers(const ScriptWrappableVisitor* visitor) const  override{}
     virtual ~IdleTask() = default;
     virtual void invoke(IdleDeadline*) = 0;
   };
@@ -56,10 +56,10 @@ class CORE_EXPORT ScriptedIdleTaskController
     static V8IdleTask* Create(V8IdleRequestCallback* callback) {
       return new V8IdleTask(callback);
     }
-    ~V8IdleTask() = default;
+    ~V8IdleTask()  override= defaul overridet;
     void invoke(IdleDeadline*) override;
-    void Trace(blink::Visitor*);
-    void TraceWrappers(const ScriptWrappableVisitor*) const;
+    void Trace(blink::Visitor*) override;
+    void TraceWrappers(const ScriptWrappableVisitor*) const override;

    private:
     explicit V8IdleTask(V8IdleRequestCallback*);

This is pretty clearly wrong.

Interestingly enough, it seems like we usually generate the right insertion... except for one file:
$ grep 'third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59' fixit_output
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:27-59:27}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:19-59:19}:" override"

It's unclear if this is specific to the jumbo build or not: in a jumbo build. Here's the current location where the plugin generates the bad replacement:
In file included from gen/third_party/WebKit/Source/core/dom/dom_jumbo_3.cc:6:
In file included from gen/third_party/WebKit/Source/core/dom/../../../../../../../../third_party/WebKit/Source/core/dom/MutationObserver.cpp:44:
In file included from ../../third_party/WebKit/Source/core/probe/CoreProbes.h:36:
In file included from ../../third_party/WebKit/Source/core/dom/Document.h:51:
../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h:34:32: warning: [chromium-style] Overriding method must be marked with 'override' or 'final'.
  ~ScriptedIdleTaskController();
                               ^
                                override
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{34:32-34:32}:" override"
../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h:36:30: warning: [chromium-style] Overriding method must be marked with 'override' or 'final'.
  void Trace(blink::Visitor*);
                             ^
                              override
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{36:30-36:30}:" override"
../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h:37:58: warning: [chromium-style] Overriding method must be marked with 'override' or 'final'.
  void TraceWrappers(const ScriptWrappableVisitor*) const;
                                                         ^
                                                          override
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{37:58-37:58}:" override"
../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h:47:77: warning: [chromium-style] Overriding method must be marked with 'override' or 'final'.
    virtual void TraceWrappers(const ScriptWrappableVisitor* visitor) const {}
                                                                            ^
                                                                             override
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{47:77-47:77}:" override"
../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h:59:27: warning: [chromium-style] Overriding method must be marked with 'override' or 'final'.
    ~V8IdleTask() = default;
                          ^
                           override
fix-it:"../../third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.h":{59:27-59:27}:" override"