Revert of Schedule garbage collection on worker threads using idle tasks

Source/core/workers/WorkerThread.cpp

Index: Source/core/workers/WorkerThread.cpp
diff --git a/Source/core/workers/WorkerThread.cpp b/Source/core/workers/WorkerThread.cpp
index 1293544be91344bb4fd1c23e47e37f91d117a970..5842471ba2fab4c37a5111ef05079c1ab08d6367 100644
--- a/Source/core/workers/WorkerThread.cpp
+++ b/Source/core/workers/WorkerThread.cpp
@@ -46,7 +46,6 @@
 #include "platform/heap/ThreadState.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/Platform.h"
-#include "public/platform/WebScheduler.h"
 #include "public/platform/WebThread.h"
 #include "public/platform/WebWaitableEvent.h"
 #include "wtf/Noncopyable.h"
@@ -56,7 +55,8 @@
 namespace blink {
 
 namespace {
-const double kLongIdlePeriodSecs = 1.0;
+const int64_t kShortIdleHandlerDelayMs = 1000;
+const int64_t kLongIdleHandlerDelayMs = 10*1000;
 
 } // namespace
 
@@ -267,7 +267,6 @@
     , m_terminated(false)
     , m_workerLoaderProxy(workerLoaderProxy)
     , m_workerReportingProxy(workerReportingProxy)
-    , m_webScheduler(nullptr)
     , m_startupData(startupData)
     , m_isolate(nullptr)
     , m_shutdownEvent(adoptPtr(Platform::current()->createWaitableEvent()))
@@ -306,24 +305,6 @@
         return 0;
     return backingThread().platformThread().threadId();
 }
-
-// TODO(alexclarke): Use base::Bind instead of this class when the repo's merge. Unfortunately we
-// can't use WTF::bind because the type-erasure for member function pointers with parameters is broken.
-class WorkerThreadIdleTask : public WebThread::IdleTask {
-public:
-    explicit WorkerThreadIdleTask(WorkerThread* thread)
-        : m_thread(thread) { }
-
-    ~WorkerThreadIdleTask() override { }
-
-    void run(double deadlineSeconds) override
-    {
-        m_thread->performIdleWork(deadlineSeconds);
-    }
-
-private:
-    RawPtr<WorkerThread> m_thread; // NOT OWNED
-};
 
 void WorkerThread::initialize()
 {
@@ -333,7 +314,6 @@
     OwnPtr<Vector<char>> cachedMetaData = m_startupData->m_cachedMetaData.release();
     V8CacheOptions v8CacheOptions = m_startupData->m_v8CacheOptions;
 
-    m_webScheduler = backingThread().platformThread().scheduler();
     {
         MutexLocker lock(m_threadStateMutex);
 
@@ -375,7 +355,7 @@
 
     postInitialize();
 
-    m_webScheduler->postIdleTaskAfterWakeup(FROM_HERE, new WorkerThreadIdleTask(this));
+    postDelayedTask(FROM_HERE, createSameThreadTask(&WorkerThread::idleHandler, this), kShortIdleHandlerDelayMs);
 }
 
 void WorkerThread::shutdown()
@@ -494,27 +474,21 @@
     return m_started && backingThread().isCurrentThread();
 }
 
-void WorkerThread::performIdleWork(double deadlineSeconds)
-{
-    double gcDeadlineSeconds = deadlineSeconds;
-
-    // The V8 GC does some GC steps (e.g. compaction) only when the idle notification is ~1s.
-    // TODO(rmcilroy): Refactor so extending the deadline like this this isn't needed.
-    if (m_webScheduler->canExceedIdleDeadlineIfRequired())
-        gcDeadlineSeconds = Platform::current()->monotonicallyIncreasingTime() + kLongIdlePeriodSecs;
-
-    if (doIdleGc(gcDeadlineSeconds))
-        m_webScheduler->postIdleTaskAfterWakeup(FROM_HERE, new WorkerThreadIdleTask(this));
-    else
-        m_webScheduler->postIdleTask(FROM_HERE, new WorkerThreadIdleTask(this));
-}
-
-bool WorkerThread::doIdleGc(double deadlineSeconds)
-{
-    bool gcFinished = false;
-    if (deadlineSeconds > Platform::current()->monotonicallyIncreasingTime())
-        gcFinished = isolate()->IdleNotificationDeadline(deadlineSeconds);
-    return gcFinished;
+void WorkerThread::idleHandler()
+{
+    ASSERT(m_workerGlobalScope.get());
+    int64_t delay = kLongIdleHandlerDelayMs;
+
+    // Do a script engine idle notification if the next event is distant enough.
+    const double kMinIdleTimespan = 0.3;
+    const double nextFireTime = PlatformThreadData::current().threadTimers().nextFireTime();
+    if (nextFireTime == 0.0 || nextFireTime > currentTime() + kMinIdleTimespan) {
+        bool hasMoreWork = !isolate()->IdleNotificationDeadline(Platform::current()->monotonicallyIncreasingTime() + 1.0);
+        if (hasMoreWork)
+            delay = kShortIdleHandlerDelayMs;
+    }
+
+    postDelayedTask(FROM_HERE, createSameThreadTask(&WorkerThread::idleHandler, this), delay);
 }
 
 void WorkerThread::postTask(const WebTraceLocation& location, PassOwnPtr<ExecutionContextTask> task)