Reduce createSameThreadTask usage in modules/

third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp

 // Copyright 2016 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 "modules/remoteplayback/RemotePlayback.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/modules/v8/RemotePlaybackAvailabilityCallback.h"
 #include "core/HTMLNames.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
-#include "core/dom/ExecutionContextTask.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/events/Event.h"
 #include "core/html/HTMLMediaElement.h"
+#include "core/inspector/InspectorInstrumentation.h"
 #include "modules/EventTargetModules.h"
 #include "platform/MemoryCoordinator.h"
 #include "platform/UserGestureIndicator.h"
 
 namespace blink {
 
 namespace {
 
 const AtomicString& remotePlaybackStateToString(WebRemotePlaybackState state) {
   DEFINE_STATIC_LOCAL(const AtomicString, connectingValue, ("connecting"));
@@ skipping 28 matching lines @@
       m_mediaElement(&element) {}
 
 const AtomicString& RemotePlayback::interfaceName() const {
   return EventTargetNames::RemotePlayback;
 }
 
 ExecutionContext* RemotePlayback::getExecutionContext() const {
   return &m_mediaElement->document();
 }
 
+static void runNotifyInitialAvailabilityTask(

[nhiroki, 2017/02/17 03:47:15]

nit: Can you move this into the anonymous namespace above instead of static
function? Using static function is also allowed[1], but it'd better to make it
consistent with existing code.

[1]
https://google.github.io/styleguide/cppguide.html#Unnamed_Namespaces_and_Stat...

[yuryu, 2017/02/17 05:14:33]

Done.

+    ExecutionContext* context,
+    std::unique_ptr<WTF::Closure> task) {
+  InspectorInstrumentation::AsyncTask asyncTask(context, task.get());
+  (*task)();
+}
+
 ScriptPromise RemotePlayback::watchAvailability(
     ScriptState* scriptState,
     RemotePlaybackAvailabilityCallback* callback) {
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
   ScriptPromise promise = resolver->promise();
 
   if (m_mediaElement->fastHasAttribute(HTMLNames::disableremoteplaybackAttr)) {
     resolver->reject(DOMException::create(
         InvalidStateError, "disableRemotePlayback attribute is present."));
     return promise;
   }
 
   if (MemoryCoordinator::isLowEndDevice()) {
     resolver->reject(DOMException::create(
         NotSupportedError,
         "Availability monitoring is not supported on this device."));
     return promise;
   }
 
   int id;
   do {
     id = getExecutionContext()->circularSequentialID();
   } while (
       !m_availabilityCallbacks
            .insert(id, TraceWrapperMember<RemotePlaybackAvailabilityCallback>(
                            this, callback))
            .isNewEntry);
 
   // Report the current availability via the callback.
-  getExecutionContext()->postTask(
-      TaskType::MediaElementEvent, BLINK_FROM_HERE,
-      createSameThreadTask(&RemotePlayback::notifyInitialAvailability,
-                           wrapPersistent(this), id),
-      "watchAvailabilityCallback");
+  // TODO(yuryu): Wrapping notifyInitialAvailability with WTF::Closure as
+  // InspectorInstrumentation requires a globally unique pointer to track tasks.
+  // We can remove the wrapper if InspectorInstrumentation returns a task id.
+  std::unique_ptr<WTF::Closure> task = WTF::bind(
+      &RemotePlayback::notifyInitialAvailability, wrapPersistent(this), id);
+  InspectorInstrumentation::asyncTaskScheduled(
+      getExecutionContext(), "watchAvailabilityCallback", task.get());
+  TaskRunnerHelper::get(TaskType::MediaElementEvent, getExecutionContext())
+      ->postTask(BLINK_FROM_HERE,
+                 WTF::bind(runNotifyInitialAvailabilityTask,
+                           wrapPersistent(getExecutionContext()),
+                           WTF::passed(std::move(task))));
 
   // TODO(avayvod): Currently the availability is tracked for each media element
   // as soon as it's created, we probably want to limit that to when the
   // page/element is visible (see https://crbug.com/597281) and has default
   // controls. If there are no default controls, we should also start tracking
   // availability on demand meaning the Promise returned by watchAvailability()
   // will be resolved asynchronously.
   resolver->resolve(id);
   return promise;
 }
@@ skipping 193 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(RemotePlayback) {
   for (auto callback : m_availabilityCallbacks.values()) {
     visitor->traceWrappers(callback);
   }
   EventTargetWithInlineData::traceWrappers(visitor);
 }
 
 }  // namespace blink