Move VTTRegion Timers to TaskRunnerTimer

third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp

Index: third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp
diff --git a/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp b/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp
index bf9b0addd00e247e7956e12fe32ff423a8cddc72..7a06a99f369f5846b43fcca38f98c6c1ef1fb7a1 100644
--- a/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp
+++ b/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.cpp
@@ -36,6 +36,7 @@
 #include "core/dom/DOMTokenList.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "core/html/HTMLDivElement.h"
 #include "core/html/track/vtt/VTTParser.h"
 #include "core/html/track/vtt/VTTScanner.h"
@@ -90,7 +91,10 @@ VTTRegion::VTTRegion()
       m_viewportAnchor(FloatPoint(defaultAnchorPointX, defaultAnchorPointY)),
       m_scroll(defaultScroll),
       m_currentTop(0),
-      m_scrollTimer(this, &VTTRegion::scrollTimerFired) {}
+      m_scrollTimer(
+          TaskRunnerHelper::get(TaskType::UnspecedTimer, (Document*)nullptr),

[maksims (do not use this acc), 2017/02/14 08:28:58]

What about this solution? I've tested it and it seemed to work.

[foolip, 2017/02/14 13:37:09]

The cast is a little suspicious. Does just nullptr not work, and is the value
here not actually used for anything?

[maksims (do not use this acc), 2017/02/16 06:44:05]

Check TaskRunnerHelper::get(). It's an overloaded function with different
parameters. Nullptr leads to ambiguous call. But if that is casted to a document
or anything else, then task runner is taken from the Platform::current().

[foolip, 2017/02/16 07:46:09]

From cs.chromium.org at a glance, I can't find any other call sites where the
second argument is always null, probably because that's a roundabout way of
writing Platform::current()->currentThread()->getWebTaskRunner().

Can you use Platform::current()->currentThread()->getWebTaskRunner() instead?

Somehow getting the right task queue from the document in which the region will
be rendered, something like PS1, feels like the other best option, but that
might require some refactoring to not have to do the std::unique_ptr thing.

[maksims (do not use this acc), 2017/02/16 09:16:22]

Done.

+          this,
+          &VTTRegion::scrollTimerFired) {}
 
 VTTRegion::~VTTRegion() {}