Revert of Do V8 GC ASAP if system memory is pressured

third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/workers/WorkerBackingThread.h"
 
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8IdleTaskRunner.h"
 #include "bindings/core/v8/V8Initializer.h"
 #include "bindings/core/v8/V8PerIsolateData.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ThreadSafeFunctional.h"
 #include "platform/WebThreadSupportingGC.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebTraceLocation.h"
 
 namespace blink {
 
-#define DEFINE_STATIC_LOCAL_WITH_LOCK(type, name, arguments) \
-    ASSERT(isolatesMutex().locked()); \
-    static type& name = *new type arguments
-
-static Mutex& isolatesMutex()
-{
-    DEFINE_THREAD_SAFE_STATIC_LOCAL(Mutex, mutex, new Mutex);
-    return mutex;
-}
-
-static HashSet<v8::Isolate*>& isolates()
-{
-    DEFINE_STATIC_LOCAL_WITH_LOCK(HashSet<v8::Isolate*>, isolates, ());
-    return isolates;
-}
-
-static void addWorkerIsolate(v8::Isolate* isolate)
-{
-    MutexLocker lock(isolatesMutex());
-    isolates().add(isolate);
-}
-
-static void removeWorkerIsolate(v8::Isolate* isolate)
-{
-    MutexLocker lock(isolatesMutex());
-    isolates().remove(isolate);
-}
-
 WorkerBackingThread::WorkerBackingThread(const char* name, bool shouldCallGCOnShutdown)
     : m_backingThread(WebThreadSupportingGC::create(name))
     , m_isOwningThread(true)
     , m_shouldCallGCOnShutdown(shouldCallGCOnShutdown)
 {
 }
 
 WorkerBackingThread::WorkerBackingThread(WebThread* thread, bool shouldCallGCOnShutdown)
     : m_backingThread(WebThreadSupportingGC::createForThread(thread))
     , m_isOwningThread(false)
@@ skipping 26 matching lines @@
         if (--m_workerScriptCount > 0)
             return;
     }
     shutdown();
 }
 
 void WorkerBackingThread::initialize()
 {
     DCHECK(!m_isolate);
     m_isolate = V8PerIsolateData::initialize();
-    addWorkerIsolate(m_isolate);
     V8Initializer::initializeWorker(m_isolate);
     m_backingThread->initialize();
 
     OwnPtr<V8IsolateInterruptor> interruptor = adoptPtr(new V8IsolateInterruptor(m_isolate));
     ThreadState::current()->addInterruptor(interruptor.release());
     ThreadState::current()->registerTraceDOMWrappers(m_isolate, V8GCController::traceDOMWrappers);
     if (RuntimeEnabledFeatures::v8IdleTasksEnabled())
         V8PerIsolateData::enableIdleTasks(m_isolate, adoptPtr(new V8IdleTaskRunner(backingThread().platformThread().scheduler())));
     if (m_isOwningThread)
         Platform::current()->didStartWorkerThread();
 }
 
 void WorkerBackingThread::shutdown()
 {
     if (m_isOwningThread)
         Platform::current()->willStopWorkerThread();
 
     V8PerIsolateData::willBeDestroyed(m_isolate);
     // TODO(yhirano): Remove this when https://crbug.com/v8/1428 is fixed.
     if (m_shouldCallGCOnShutdown) {
         // This statement runs only in tests.
         V8GCController::collectAllGarbageForTesting(m_isolate);
     }
     m_backingThread->shutdown();
 
     V8PerIsolateData::destroy(m_isolate);
-    removeWorkerIsolate(m_isolate);
     m_isolate = nullptr;
 }
 
-// static
-void WorkerBackingThread::MemoryPressureNotificationToWorkerThreadIsolates(
-    v8::MemoryPressureLevel level)
-{
-    MutexLocker lock(isolatesMutex());
-    for (v8::Isolate* isolate : isolates())
-        isolate->MemoryPressureNotification(level);
-}
-
 } // namespace blink