Revert of Implement timers by posting delayed 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 d3b4156f03aa9f4e4999b71dfed1ec6575cbcd0a..ff101dd1e8a5f4749ca24b0bb1e505e6c8bed7e5 100644
--- a/Source/core/workers/WorkerThread.cpp
+++ b/Source/core/workers/WorkerThread.cpp
@@ -38,8 +38,10 @@
 #include "core/workers/WorkerClients.h"
 #include "core/workers/WorkerReportingProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
+#include "platform/PlatformThreadData.h"
 #include "platform/Task.h"
 #include "platform/ThreadSafeFunctional.h"
+#include "platform/ThreadTimers.h"
 #include "platform/heap/SafePoint.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/weborigin/KURL.h"
@@ -109,6 +111,100 @@
     return workerThreads().size();
 }
 
+class WorkerThreadCancelableTask final : public ExecutionContextTask {
+    WTF_MAKE_NONCOPYABLE(WorkerThreadCancelableTask); WTF_MAKE_FAST_ALLOCATED(WorkerThreadCancelableTask);
+public:
+    static PassOwnPtr<WorkerThreadCancelableTask> create(PassOwnPtr<Closure> closure)
+    {
+        return adoptPtr(new WorkerThreadCancelableTask(closure));
+    }
+
+    virtual ~WorkerThreadCancelableTask() { }
+
+    virtual void performTask(ExecutionContext*) override
+    {
+        if (!m_taskCanceled)
+            (*m_closure)();
+    }
+
+    WeakPtr<WorkerThreadCancelableTask> createWeakPtr() { return m_weakFactory.createWeakPtr(); }
+    void cancelTask() { m_taskCanceled = true; }
+
+private:
+    explicit WorkerThreadCancelableTask(PassOwnPtr<Closure> closure)
+        : m_closure(closure)
+        , m_weakFactory(this)
+        , m_taskCanceled(false)
+    { }
+
+    OwnPtr<Closure> m_closure;
+    WeakPtrFactory<WorkerThreadCancelableTask> m_weakFactory;
+    bool m_taskCanceled;
+};
+
+class WorkerSharedTimer : public SharedTimer {
+public:
+    explicit WorkerSharedTimer(WorkerThread* workerThread)
+        : m_workerThread(workerThread)
+        , m_running(false)
+    { }
+
+    typedef void (*SharedTimerFunction)();
+    virtual void setFiredFunction(SharedTimerFunction func)
+    {
+        m_sharedTimerFunction = func;
+    }
+
+    virtual void setFireInterval(double interval)
+    {
+        ASSERT(m_sharedTimerFunction);
+
+        // See BlinkPlatformImpl::setSharedTimerFireInterval for explanation of
+        // why ceil is used in the interval calculation.
+        int64_t delay = static_cast<int64_t>(ceil(interval * 1000));
+
+        if (delay < 0) {
+            delay = 0;
+        }
+
+        m_running = true;
+
+        if (m_lastQueuedTask.get())
+            m_lastQueuedTask->cancelTask();
+
+        // Now queue the task as a cancellable one.
+        OwnPtr<WorkerThreadCancelableTask> task = WorkerThreadCancelableTask::create(bind(&WorkerSharedTimer::OnTimeout, this));
+        m_lastQueuedTask = task->createWeakPtr();
+        m_workerThread->postDelayedTask(FROM_HERE, task.release(), delay);
+    }
+
+    virtual void stop()
+    {
+        m_running = false;
+        m_lastQueuedTask = nullptr;
+    }
+
+private:
+    void OnTimeout()
+    {
+        ASSERT(m_workerThread->workerGlobalScope());
+
+        m_lastQueuedTask = nullptr;
+
+        if (m_sharedTimerFunction && m_running && !m_workerThread->workerGlobalScope()->isClosing())
+            m_sharedTimerFunction();
+    }
+
+    WorkerThread* m_workerThread;
+    SharedTimerFunction m_sharedTimerFunction;
+    bool m_running;
+
+    // The task to run OnTimeout, if any. While OnTimeout resets
+    // m_lastQueuedTask, this must be a weak pointer because the
+    // worker runloop may delete the task as it is shutting down.
+    WeakPtr<WorkerThreadCancelableTask> m_lastQueuedTask;
+};
+
 class WorkerThreadTask : public WebThread::Task {
     WTF_MAKE_NONCOPYABLE(WorkerThreadTask); WTF_MAKE_FAST_ALLOCATED(WorkerThreadTask);
 public:
@@ -224,6 +320,8 @@
         m_isolate = initializeIsolate();
         m_workerGlobalScope = createWorkerGlobalScope(startupData);
         m_workerGlobalScope->scriptLoaded(sourceCode.length(), cachedMetaData.get() ? cachedMetaData->size() : 0);
+
+        PlatformThreadData::current().threadTimers().setSharedTimer(adoptPtr(new WorkerSharedTimer(this)));
     }
     m_webScheduler = backingThread().platformThread().scheduler();
 
@@ -258,6 +356,7 @@
         m_shutdown = true;
     }
 
+    PlatformThreadData::current().threadTimers().setSharedTimer(nullptr);
     workerGlobalScope()->dispose();
     willDestroyIsolate();
 
@@ -284,6 +383,9 @@
     workerReportingProxy().workerThreadTerminated();
 
     m_terminationEvent->signal();
+
+    // Clean up PlatformThreadData before WTF::WTFThreadData goes away!
+    PlatformThreadData::current().destroy();
 }