Move ScrollableArea timer to TaskRunnerTimer.

third_party/WebKit/Source/core/frame/VisualViewport.cpp

Index: third_party/WebKit/Source/core/frame/VisualViewport.cpp
diff --git a/third_party/WebKit/Source/core/frame/VisualViewport.cpp b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
index 7899bfb739fa6ae38580bd46562acd8c67d122a4..9d7b89b824cf651fc44fd6de55478af32b2658e3 100644
--- a/third_party/WebKit/Source/core/frame/VisualViewport.cpp
+++ b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
@@ -31,6 +31,7 @@
 #include "core/frame/VisualViewport.h"
 
 #include "core/dom/DOMNodeIds.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ -629,6 +630,10 @@ IntRect VisualViewport::visibleContentRect(
   return rect;
 }
 
+RefPtr<WebTaskRunner> VisualViewport::getTimerTaskRunner() const {
+  return TaskRunnerHelper::get(TaskType::UnspecedTimer, mainFrame());
+}
+
 void VisualViewport::updateScrollOffset(const ScrollOffset& position,
                                         ScrollType scrollType) {
   if (didSetScaleOrLocation(m_scale, FloatPoint(position)) &&