Use per-frame task runner in XHR

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp

 /*
  * Copyright (C) 2010 Julien Chaffraix <jchaffraix@webkit.org>  All right reserved.
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.h"
 
 #include "core/EventTypeNames.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "core/events/ProgressEvent.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/xmlhttprequest/XMLHttpRequest.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebScheduler.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Assertions.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 static const double kMinimumProgressEventDispatchingIntervalInSeconds = .05; // 50 ms per specification.
 
+// static
+XMLHttpRequestProgressEventThrottle* XMLHttpRequestProgressEventThrottle::create(XMLHttpRequest* eventTarget)
+{
+    return new XMLHttpRequestProgressEventThrottle(eventTarget, TaskRunnerHelper::get(TaskType::Networking, eventTarget->getExecutionContext())->clone());
+}
+
 XMLHttpRequestProgressEventThrottle::DeferredEvent::DeferredEvent()
 {
     clear();
 }
 
 void XMLHttpRequestProgressEventThrottle::DeferredEvent::set(bool lengthComputable, unsigned long long loaded, unsigned long long total)
 {
     m_isSet = true;
 
     m_lengthComputable = lengthComputable;
@@ skipping 12 matching lines @@
 
 Event* XMLHttpRequestProgressEventThrottle::DeferredEvent::take()
 {
     ASSERT(m_isSet);
 
     Event* event = ProgressEvent::create(EventTypeNames::progress, m_lengthComputable, m_loaded, m_total);
     clear();
     return event;
 }
 
-XMLHttpRequestProgressEventThrottle::XMLHttpRequestProgressEventThrottle(XMLHttpRequest* target)
-    : TimerBase(Platform::current()->currentThread()->scheduler()->timerTaskRunner())
+XMLHttpRequestProgressEventThrottle::XMLHttpRequestProgressEventThrottle(XMLHttpRequest* target, std::unique_ptr<WebTaskRunner> taskRunner)
+    : TimerBase(taskRunner.get())
+    , m_taskRunner(std::move(taskRunner))

[dcheng, 2016/08/24 23:30:34]

I'm a bit confused why we need to clone() and keep this alive manually. Why is
it not normally a problem (and why wasn't it a problem before)?

[haraken, 2016/08/24 23:51:58]

It's normally a problem today. Currently we need to call clone() whenever we
store a pointer to the per-frame scheduler on some objects. This issue will be
gone once we move WebTaskRunner to Oilpan's heap and start using
Member<WebTaskRunner>.

In this particular case, it was not a problem before because
Platform::current()->currentThread()->scheduler() is not a per-frame scheduler.
The scheduler keeps alive the underlying task runners until the renderer stops.

     , m_target(target)
     , m_hasDispatchedProgressProgressEvent(false)
 {
     ASSERT(target);
 }
 
 XMLHttpRequestProgressEventThrottle::~XMLHttpRequestProgressEventThrottle()
 {
 }
 
@@ skipping 87 matching lines @@
     // event-handler could insert new active DOM objects to the list.
     startOneShot(0, BLINK_FROM_HERE);
 }
 
 DEFINE_TRACE(XMLHttpRequestProgressEventThrottle)
 {
     visitor->trace(m_target);
 }
 
 } // namespace blink