Revert of Associate SuspendableTimer with frame's timer task queue.

third_party/WebKit/Source/core/frame/SuspendableTimer.cpp

Index: third_party/WebKit/Source/core/frame/SuspendableTimer.cpp
diff --git a/third_party/WebKit/Source/core/frame/SuspendableTimer.cpp b/third_party/WebKit/Source/core/frame/SuspendableTimer.cpp
index 89e0ac1e81de685877fed5254e342abeab033cfd..537501572e5ca621fc7fa1e4bbc6cf549945233a 100644
--- a/third_party/WebKit/Source/core/frame/SuspendableTimer.cpp
+++ b/third_party/WebKit/Source/core/frame/SuspendableTimer.cpp
@@ -26,8 +26,6 @@
 
 #include "core/frame/SuspendableTimer.h"
 
-#include "core/dom/TaskRunnerHelper.h"
-
 namespace blink {
 
 namespace {
@@ -36,7 +34,7 @@
 }
 
 SuspendableTimer::SuspendableTimer(ExecutionContext* context)
-    : TimerBase(TaskRunnerHelper::get(TaskType::Timer, context))
+    : TimerBase(TimerBase::getTimerTaskRunner())
     , ActiveDOMObject(context)
     , m_nextFireInterval(kNextFireIntervalInvalid)
     , m_repeatInterval(0)
@@ -44,7 +42,6 @@
     , m_suspended(false)
 #endif
 {
-    DCHECK(context);
 }
 
 SuspendableTimer::~SuspendableTimer()