content: Add RendererScheduler.

content/renderer/scheduler/web_scheduler_impl.cc

Index: content/renderer/scheduler/web_scheduler_impl.cc
diff --git a/content/renderer/scheduler/web_scheduler_impl.cc b/content/renderer/scheduler/web_scheduler_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ea4eeea8fe4a557a2f94454585c606af26cb5629
--- /dev/null
+++ b/content/renderer/scheduler/web_scheduler_impl.cc
@@ -0,0 +1,43 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/scheduler/web_scheduler_impl.h"
+
+#include "base/bind.h"
+#include "content/renderer/scheduler/renderer_scheduler.h"
+#include "third_party/WebKit/public/platform/WebTraceLocation.h"
+
+namespace content {
+
+WebSchedulerImpl::WebSchedulerImpl(RendererScheduler* renderer_scheduler)
+    : renderer_scheduler_(renderer_scheduler),
+      idle_task_runner_(renderer_scheduler_->IdleTaskRunner()) {
+}
+
+WebSchedulerImpl::~WebSchedulerImpl() {
+}
+
+bool WebSchedulerImpl::shouldYieldForHighPriorityWork() {
+  return renderer_scheduler_->ShouldYieldForHighPriorityWork();
+}
+
+void WebSchedulerImpl::runIdleTask(blink::WebScheduler::IdleTask* task,
+                                   base::TimeTicks deadline) {
+  task->run(deadline.ToInternalValue() /
+            static_cast<double>(base::Time::kMicrosecondsPerSecond));
+}
+
+void WebSchedulerImpl::postIdleTask(const blink::WebTraceLocation& web_location,
+                                    blink::WebScheduler::IdleTask* task) {
+  tracked_objects::Location location(
+      web_location.functionName(), web_location.fileName(), -1, nullptr);
+  idle_task_runner_->PostIdleTask(

[alexclarke, 2014/10/27 17:35:29]

From a defensive programming PoV I think we should track if shutdown has been
called and make this function exit if so.  Otherwise if this function gets
called, we risk accessing deleted memory.

[rmcilroy, 2014/10/27 18:18:02]

I disagree - it is OK to post to the task runners when the scheduler is
shutdown, the tasks just get silently dropped and deleted so there shouldn't be
a risk of memory corruption.  I think tracking shutdown in two places is overly
complex - if we track it here, should we also track it where we are posting to
the compositor or default task runners?  What happens if we call shutdown from a
different entry point (e.g., within chrome)?  WDYT?

[alexclarke, 2014/10/27 18:28:17]

Ah TaskRunner is refcounted.  My concern is moot. 

+      location, base::Bind(&WebSchedulerImpl::runIdleTask, base::Owned(task)));
+}
+
+void WebSchedulerImpl::shutdown() {
+  return renderer_scheduler_->Shutdown();
+}
+
+}  // namespace content