Revert of Implement timers by posting delayed tasks

Source/platform/ThreadTimers.cpp

Index: Source/platform/ThreadTimers.cpp
diff --git a/Source/platform/ThreadTimers.cpp b/Source/platform/ThreadTimers.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f358874b07931a5a03b94c71147dc945989479a1
--- /dev/null
+++ b/Source/platform/ThreadTimers.cpp
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2009 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "platform/ThreadTimers.h"
+
+#include "platform/PlatformThreadData.h"
+#include "platform/SharedTimer.h"
+#include "platform/Timer.h"
+#include "platform/TraceEvent.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebScheduler.h"
+#include "wtf/AddressSanitizer.h"
+#include "wtf/CurrentTime.h"
+#include "wtf/MainThread.h"
+
+namespace blink {
+
+// Fire timers for this length of time, and then quit to let the run loop process user input events.
+// 100ms is about a perceptable delay in UI, so use a half of that as a threshold.
+// This is to prevent UI freeze when there are too many timers or machine performance is low.
+static const double maxDurationOfFiringTimers = 0.050;
+
+// Timers are created, started and fired on the same thread, and each thread has its own ThreadTimers
+// copy to keep the heap and a set of currently firing timers.
+
+static PassOwnPtr<MainThreadSharedTimer> mainThreadSharedTimer()
+{
+    return adoptPtr(new MainThreadSharedTimer);
+}
+
+ThreadTimers::ThreadTimers()
+    : m_sharedTimer(0)
+    , m_firingTimers(false)
+    , m_pendingSharedTimerFireTime(0)
+{
+    if (isMainThread())
+        setSharedTimer(mainThreadSharedTimer());
+}
+
+// A worker thread may initialize SharedTimer after some timers are created.
+// Also, SharedTimer can be replaced with 0 before all timers are destroyed.
+void ThreadTimers::setSharedTimer(PassOwnPtr<SharedTimer> sharedTimer)
+{
+    if (m_sharedTimer) {
+        m_sharedTimer->setFiredFunction(0);
+        m_sharedTimer->stop();
+        m_pendingSharedTimerFireTime = 0;
+    }
+
+    m_sharedTimer = sharedTimer;
+
+    if (m_sharedTimer) {
+        m_sharedTimer->setFiredFunction(ThreadTimers::sharedTimerFired);
+        updateSharedTimer();
+    }
+}
+
+NO_LAZY_SWEEP_SANITIZE_ADDRESS
+void ThreadTimers::updateSharedTimer()
+{
+    if (!m_sharedTimer)
+        return;
+
+    if (m_firingTimers || m_timerHeap.isEmpty()) {
+        m_pendingSharedTimerFireTime = 0;
+        m_sharedTimer->stop();
+    } else {
+        double nextFireTime = m_timerHeap.first()->m_nextFireTime;
+        double currentMonotonicTime = monotonicallyIncreasingTime();
+        if (m_pendingSharedTimerFireTime) {
+            // No need to restart the timer if both the pending fire time and the new fire time are in the past.
+            if (m_pendingSharedTimerFireTime <= currentMonotonicTime && nextFireTime <= currentMonotonicTime)
+                return;
+        }
+        m_pendingSharedTimerFireTime = nextFireTime;
+        m_sharedTimer->setFireInterval(std::max(nextFireTime - currentMonotonicTime, 0.0));
+    }
+}
+
+void ThreadTimers::sharedTimerFired()
+{
+    TRACE_EVENT_SET_SAMPLING_STATE("blink", "BlinkInternal");
+
+    // Redirect to non-static method.
+    PlatformThreadData::current().threadTimers().sharedTimerFiredInternal();
+
+    TRACE_EVENT_SET_SAMPLING_STATE("blink", "Sleeping");
+}
+
+NO_LAZY_SWEEP_SANITIZE_ADDRESS
+void ThreadTimers::sharedTimerFiredInternal()
+{
+    // Do a re-entrancy check.
+    if (m_firingTimers)
+        return;
+    m_firingTimers = true;
+    m_pendingSharedTimerFireTime = 0;
+
+    double fireTime = monotonicallyIncreasingTime();
+    double timeToQuit = fireTime + maxDurationOfFiringTimers;
+
+    while (!m_timerHeap.isEmpty() && m_timerHeap.first()->m_nextFireTime <= fireTime) {
+        TimerBase& timer = *m_timerHeap.first();
+        timer.m_nextFireTime = 0;
+        timer.m_unalignedNextFireTime = 0;
+        timer.heapDeleteMin();
+
+        double interval = timer.repeatInterval();
+        timer.setNextFireTime(interval ? fireTime + interval : 0);
+
+        TRACE_EVENT2("blink", "ThreadTimers::sharedTimerFiredInternal",
+            "src_file", timer.location().fileName(),
+            "src_func", timer.location().functionName());
+
+        // Once the timer has been fired, it may be deleted, so do nothing else with it after this point.
+        timer.fired();
+
+        // Catch the case where the timer asked timers to fire in a nested event loop, or we are over time limit.
+        if (!m_firingTimers || timeToQuit < monotonicallyIncreasingTime()
+            || (isMainThread() && Platform::current()->currentThread()->scheduler()->shouldYieldForHighPriorityWork()))
+            break;
+    }
+
+    m_firingTimers = false;
+
+    updateSharedTimer();
+}
+
+} // namespace blink