Revert of Do V8 GC ASAP if system memory is pressured

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

Index: third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp b/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
index 7267083c7053962b89296c7c05e654b6b6691cce..040ce92ea79208362ca3f48cfceb67291d092614 100644
--- a/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
@@ -16,34 +16,6 @@
 #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))
@@ -91,7 +63,6 @@
 {
     DCHECK(!m_isolate);
     m_isolate = V8PerIsolateData::initialize();
-    addWorkerIsolate(m_isolate);
     V8Initializer::initializeWorker(m_isolate);
     m_backingThread->initialize();
 
@@ -118,17 +89,7 @@
     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