Use per-frame task runner in XHR

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

Index: third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp
diff --git a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp
index 9bfb0444231bbee6dabf724534e563861e2038a0..b485a2fb89ae1416d6ff8ab98aeec7ce782599b4 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.cpp
@@ -27,6 +27,7 @@
 #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"
@@ -41,6 +42,12 @@ 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();
@@ -73,8 +80,9 @@ Event* XMLHttpRequestProgressEventThrottle::DeferredEvent::take()
     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)
 {