Patch 2/3 to get WebScheduler via WebThread

Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp

Index: Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp
diff --git a/Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp b/Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp
index 3e43c3d4332573e6ccfbede63dd9e1087cd724c6..6b061075d7ffdbf4611d4c791731950d4ca6f287 100644
--- a/Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp
+++ b/Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp
@@ -303,6 +303,12 @@ private:
 
         virtual void exitRunLoop() override { ASSERT_NOT_REACHED(); }
 
+        virtual WebScheduler* scheduler() const override
+        {
+            ASSERT_NOT_REACHED();
+            return nullptr;
+        }
+
     private:
         TaskObserver* m_taskObserver;
         Task* m_task;