scheduler: Add an unthrottled per-frame task runner

third_party/WebKit/Source/core/loader/EmptyClients.cpp

Index: third_party/WebKit/Source/core/loader/EmptyClients.cpp
diff --git a/third_party/WebKit/Source/core/loader/EmptyClients.cpp b/third_party/WebKit/Source/core/loader/EmptyClients.cpp
index 3a74c627948b8a1f4f63363c1862cf3aec2f8178..dda06dbcdbbcc9c786af814766cf5c3ab07dfc22 100644
--- a/third_party/WebKit/Source/core/loader/EmptyClients.cpp
+++ b/third_party/WebKit/Source/core/loader/EmptyClients.cpp
@@ -73,6 +73,7 @@ public:
     void setFrameVisible(bool) override { }
     WebTaskRunner* loadingTaskRunner() override;
     WebTaskRunner* timerTaskRunner() override;
+    WebTaskRunner* unthrottledTaskRunner() override;
 };
 
 WebTaskRunner* EmptyFrameScheduler::loadingTaskRunner()
@@ -85,6 +86,11 @@ WebTaskRunner* EmptyFrameScheduler::timerTaskRunner()
     return Platform::current()->currentThread()->getWebTaskRunner();
 }
 
+WebTaskRunner* EmptyFrameScheduler::unthrottledTaskRunner()
+{
+    return Platform::current()->currentThread()->getWebTaskRunner();
+}
+
 PopupMenu* EmptyChromeClient::openPopupMenu(LocalFrame&, HTMLSelectElement&)
 {
     return new EmptyPopupMenu();