Introduce WebTaskRunner Patch 3/5

Source/platform/Timer.h

Index: Source/platform/Timer.h
diff --git a/Source/platform/Timer.h b/Source/platform/Timer.h
index ec2621b0508cb0db7ca3e7addab133e2fc2ec257..5ee63b819918f5f35418da2afa457343177d791e 100644
--- a/Source/platform/Timer.h
+++ b/Source/platform/Timer.h
@@ -28,6 +28,7 @@
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/Handle.h"
+#include "public/platform/WebTaskRunner.h"
 #include "public/platform/WebTraceLocation.h"
 #include "wtf/AddressSanitizer.h"
 #include "wtf/Noncopyable.h"
@@ -87,7 +88,7 @@ private:
 
     void runInternal();
 
-    class CancellableTimerTask final : public WebThread::Task {
+    class CancellableTimerTask final : public WebTaskRunner::Task {
         WTF_MAKE_NONCOPYABLE(CancellableTimerTask);
     public:
         explicit CancellableTimerTask(TimerBase* timer) : m_timer(timer) { }