Revert of Remove WorkerBackingThread::scriptCount

third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp

 // Copyright 2015 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 "modules/compositorworker/CompositorWorkerThread.h"
 
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8Initializer.h"
 #include "core/workers/InProcessWorkerObjectProxy.h"
 #include "core/workers/WorkerBackingThread.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
 #include "platform/ThreadSafeFunctional.h"
 #include "platform/TraceEvent.h"
 #include "platform/WaitableEvent.h"
 #include "platform/WebThreadSupportingGC.h"
 #include "public/platform/Platform.h"
-#include "wtf/Assertions.h"
 
 namespace blink {
 
 namespace {
 
 // This is a singleton class holding the compositor worker thread in this
 // renderer process. BackingThreadHolder::m_thread is cleared by
 // ModulesInitializer::shutdown.
 // See WorkerThread::terminateAndWaitForAllWorkers for the process shutdown
 // case.
 class BackingThreadHolder {
 public:
     static BackingThreadHolder& instance()
     {
         MutexLocker locker(holderInstanceMutex());
         return *s_instance;
     }
 
     static void ensureInstance()
     {
         if (!s_instance)
             s_instance = new BackingThreadHolder;
     }
 
+    static void terminateExecution()
+    {
+        MutexLocker locker(holderInstanceMutex());
+        if (s_instance && s_instance->m_initialized) {
+            s_instance->thread()->isolate()->TerminateExecution();
+            s_instance->m_terminatingExecution = true;
+        }
+    }
+
     static void clear()
     {
         MutexLocker locker(holderInstanceMutex());
         if (s_instance) {
+            DCHECK(!s_instance->m_initialized || s_instance->m_terminatingExecution);
             s_instance->shutdownAndWait();
             delete s_instance;
             s_instance = nullptr;
         }
     }
 
     static void createForTest()
     {
         MutexLocker locker(holderInstanceMutex());
         DCHECK_EQ(nullptr, s_instance);
@@ skipping 12 matching lines @@
 
     static Mutex& holderInstanceMutex()
     {
         DEFINE_THREAD_SAFE_STATIC_LOCAL(Mutex, holderMutex, new Mutex);
         return holderMutex;
     }
 
     void initializeOnThread()
     {
         MutexLocker locker(holderInstanceMutex());
-        DCHECK(!m_initialized);
-        m_thread->initialize();
+        DCHECK_EQ(0u, m_thread->workerScriptCount()) << "BackingThreadHolder should be the first to attach to WorkerBackingThread";
+        m_thread->attach();
         m_initialized = true;
     }
 
     void shutdownAndWait()
     {
         DCHECK(isMainThread());
         WaitableEvent doneEvent;
         m_thread->backingThread().postTask(BLINK_FROM_HERE, threadSafeBind(&BackingThreadHolder::shutdownOnThread, AllowCrossThreadAccess(this), AllowCrossThreadAccess(&doneEvent)));
         doneEvent.wait();
     }
 
     void shutdownOnThread(WaitableEvent* doneEvent)
     {
-        m_thread->shutdown();
+        DCHECK_EQ(1u, m_thread->workerScriptCount()) << "BackingThreadHolder should be the last to detach from WorkerBackingThread";
+        m_thread->detach();
         doneEvent->signal();
     }
 
     OwnPtr<WorkerBackingThread> m_thread;
+    bool m_terminatingExecution = false;
     bool m_initialized = false;
 
     static BackingThreadHolder* s_instance;
 };
 
 BackingThreadHolder* BackingThreadHolder::s_instance = nullptr;
 
 } // namespace
 
 PassOwnPtr<CompositorWorkerThread> CompositorWorkerThread::create(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, InProcessWorkerObjectProxy& workerObjectProxy, double timeOrigin)
@@ skipping 24 matching lines @@
     TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::createWorkerGlobalScope");
     return CompositorWorkerGlobalScope::create(this, std::move(startupData), m_timeOrigin);
 }
 
 void CompositorWorkerThread::ensureSharedBackingThread()
 {
     DCHECK(isMainThread());
     BackingThreadHolder::ensureInstance();
 }
 
+void CompositorWorkerThread::terminateExecution()
+{
+    DCHECK(isMainThread());
+    BackingThreadHolder::terminateExecution();
+}
+
 void CompositorWorkerThread::clearSharedBackingThread()
 {
     DCHECK(isMainThread());
     BackingThreadHolder::clear();
 }
 
 void CompositorWorkerThread::createSharedBackingThreadForTest()
 {
     BackingThreadHolder::createForTest();
 }
 
 } // namespace blink