Convert MediaControlElements timer to UnspecedTimer per-frame TaskRunnerTimer.

third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp

Index: third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
index b5a95e3f43509d32fd5744917377a56a92e13d7c..cf7b4fa804d50f0a4ca835a344bdfd1632dce606 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
@@ -32,6 +32,7 @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/InputTypeNames.h"
 #include "core/dom/ClientRect.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "core/dom/Text.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/events/MouseEvent.h"
@@ -130,8 +131,10 @@ MediaControlPanelElement::MediaControlPanelElement(MediaControls& mediaControls)
     : MediaControlDivElement(mediaControls, MediaControlsPanel),
       m_isDisplayed(false),
       m_opaque(true),
-      m_transitionTimer(this, &MediaControlPanelElement::transitionTimerFired) {
-}
+      m_transitionTimer(TaskRunnerHelper::get(TaskType::MediaElementEvent,

[mlamouri (slow - plz ping), 2017/01/23 00:00:39]

Ideally, MediaControlElements shouldn't be noticeably different from custom
controls in JS. Is there a generic TaskType that could be used instead of
MediaElementEvent?

+                                              &mediaControls.document()),
+                        this,
+                        &MediaControlPanelElement::transitionTimerFired) {}
 
 MediaControlPanelElement* MediaControlPanelElement::create(
     MediaControls& mediaControls) {