Schedule bitmap animation timers on the compositor task runner.

third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc
index 2adcdb1f0d5237ede3953a8e959806abb71f1b3d..284f7df4df1a33c5778a0faf6a8a8b851ab0bf19 100644
--- a/third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/child/web_scheduler_impl.cc
@@ -70,6 +70,11 @@ blink::WebTaskRunner* WebSchedulerImpl::TimerTaskRunner() {
   return timer_web_task_runner_.Get();
 }
 
+blink::WebTaskRunner* WebSchedulerImpl::CompositorTaskRunner() {
+  NOTREACHED();
+  return nullptr;
+}
+
 std::unique_ptr<blink::WebViewScheduler>
 WebSchedulerImpl::CreateWebViewScheduler(
     InterventionReporter*,