Introduce WorkerBackingThread

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

Index: third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp
index 004e2e6db6cabb502b8a186a003a2d60d4c0c196..e68c9a31986aa39c1290c0153b420f675cce1856 100644
--- a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp
@@ -6,6 +6,7 @@
 
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8Initializer.h"
+#include "core/workers/WorkerBackingThread.h"
 #include "core/workers/WorkerObjectProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
@@ -17,122 +18,26 @@ namespace blink {
 
 namespace {
 
-void destroyThread(WebThreadSupportingGC* thread)
-{
-    ASSERT(isMainThread());
-    // The destructor for |thread| will block until all tasks have completed.
-    // This guarantees that shutdown will finish before the thread is destroyed.
-    delete thread;
-}
-
-class CompositorWorkerSharedState {
+class BackingThreadHolder {
 public:
-    static CompositorWorkerSharedState& instance()
-    {
-        DEFINE_THREAD_SAFE_STATIC_LOCAL(CompositorWorkerSharedState, compositorWorkerSharedState, (new CompositorWorkerSharedState()));
-        return compositorWorkerSharedState;
-    }
-
-    WebThreadSupportingGC* compositorWorkerThread()
-    {
-        MutexLocker lock(m_mutex);
-        if (!m_thread && isMainThread()) {
-            ASSERT(!m_workerCount);
-            WebThread* platformThread = Platform::current()->compositorThread();
-            m_thread = WebThreadSupportingGC::createForThread(platformThread);
-        }
-        return m_thread.get();
-    }
-
-    void initializeBackingThread()
-    {
-        MutexLocker lock(m_mutex);
-        ASSERT(m_thread->isCurrentThread());
-        ++m_workerCount;
-        if (m_workerCount > 1)
-            return;
-
-        m_thread->initialize();
-
-        // Initialize the isolate at the same time.
-        ASSERT(!m_isolate);
-        m_isolate = V8PerIsolateData::initialize();
-        V8Initializer::initializeWorker(m_isolate);
-
-        OwnPtr<V8IsolateInterruptor> interruptor = adoptPtr(new V8IsolateInterruptor(m_isolate));
-        ThreadState::current()->addInterruptor(interruptor.release());
-        ThreadState::current()->registerTraceDOMWrappers(m_isolate, V8GCController::traceDOMWrappers);
-    }
-
-    void shutdownBackingThread()
-    {
-        MutexLocker lock(m_mutex);
-        ASSERT(m_thread->isCurrentThread());
-        ASSERT(m_workerCount > 0);
-        --m_workerCount;
-        if (m_workerCount == 0) {
-            m_thread->shutdown();
-            Platform::current()->mainThread()->getWebTaskRunner()->postTask(
-                BLINK_FROM_HERE, threadSafeBind(destroyThread, AllowCrossThreadAccess(m_thread.leakPtr())));
-        }
-    }
-
-    v8::Isolate* initializeIsolate()
-    {
-        MutexLocker lock(m_mutex);
-        ASSERT(m_thread->isCurrentThread());
-        ASSERT(m_isolate);
-        // It is safe to use the existing isolate even if TerminateExecution() has been
-        // called on it, without calling CancelTerminateExecution().
-        return m_isolate;
-    }
-
-    void willDestroyIsolate()
-    {
-        MutexLocker lock(m_mutex);
-        ASSERT(m_thread->isCurrentThread());
-        if (m_workerCount == 1)
-            V8PerIsolateData::willBeDestroyed(m_isolate);
-    }
-
-    void destroyIsolate()
-    {
-        MutexLocker lock(m_mutex);
-        if (!m_thread) {
-            ASSERT(m_workerCount == 0);
-            V8PerIsolateData::destroy(m_isolate);
-            m_isolate = nullptr;
-        }
-    }
-
-    void terminateV8Execution()
+    static BackingThreadHolder& instance()
     {
-        MutexLocker lock(m_mutex);
-        ASSERT(isMainThread() || m_thread->isCurrentThread());
-        if (m_workerCount > 1)
-            return;
-
-        m_isolate->TerminateExecution();
-    }
-
-    bool hasThreadForTest()
-    {
-        return m_thread;
+        DEFINE_THREAD_SAFE_STATIC_LOCAL(BackingThreadHolder, holder, new BackingThreadHolder);
+        return holder;
     }
 
-    bool hasIsolateForTest()
+    WorkerBackingThread* thread() { return m_thread.get(); }
+    void clear() { m_thread = nullptr; }
+    void resetForTest()
     {
-        return m_isolate;
+        ASSERT(!m_thread || (m_thread->workerScriptCount() == 0));
+        m_thread = WorkerBackingThread::createForTest(Platform::current()->compositorThread());
     }
 
 private:
-    CompositorWorkerSharedState() {}
-    ~CompositorWorkerSharedState() {}
+    BackingThreadHolder() : m_thread(WorkerBackingThread::create(Platform::current()->compositorThread())) {}
 
-    Mutex m_mutex;
-    OwnPtr<WebThreadSupportingGC> m_thread;
-    int m_workerCount = 0;
-    v8::Isolate* m_isolate = nullptr;
+    OwnPtr<WorkerBackingThread> m_thread;
 };
 
 } // namespace
@@ -155,9 +60,9 @@ CompositorWorkerThread::~CompositorWorkerThread()
 {
 }
 
-WebThreadSupportingGC* CompositorWorkerThread::sharedBackingThread()
+WorkerBackingThread& CompositorWorkerThread::workerBackingThread()
 {
-    return CompositorWorkerSharedState::instance().compositorWorkerThread();
+    return *BackingThreadHolder::instance().thread();
 }
 
 WorkerGlobalScope*CompositorWorkerThread::createWorkerGlobalScope(PassOwnPtr<WorkerThreadStartupData> startupData)
@@ -166,54 +71,14 @@ WorkerGlobalScope*CompositorWorkerThread::createWorkerGlobalScope(PassOwnPtr<Wor
     return CompositorWorkerGlobalScope::create(this, startupData, m_timeOrigin);
 }
 
-WebThreadSupportingGC& CompositorWorkerThread::backingThread()
-{
-    return *CompositorWorkerSharedState::instance().compositorWorkerThread();
-}
-
-void CompositorWorkerThread::initializeBackingThread()
-{
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::initializeBackingThread");
-    CompositorWorkerSharedState::instance().initializeBackingThread();
-}
-
-void CompositorWorkerThread::shutdownBackingThread()
-{
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::shutdownBackingThread");
-    CompositorWorkerSharedState::instance().shutdownBackingThread();
-}
-
-v8::Isolate* CompositorWorkerThread::initializeIsolate()
-{
-    return CompositorWorkerSharedState::instance().initializeIsolate();
-}
-
-void CompositorWorkerThread::willDestroyIsolate()
-{
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::willDestroyIsolate");
-    CompositorWorkerSharedState::instance().willDestroyIsolate();
-}
-
-void CompositorWorkerThread::destroyIsolate()
-{
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::destroyIsolate");
-    CompositorWorkerSharedState::instance().destroyIsolate();
-}
-
-void CompositorWorkerThread::terminateV8Execution()
-{
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::terminateV8Execution");
-    CompositorWorkerSharedState::instance().terminateV8Execution();
-}
-
-bool CompositorWorkerThread::hasThreadForTest()
+void CompositorWorkerThread::clearSharedBackingThread()
 {
-    return CompositorWorkerSharedState::instance().hasThreadForTest();
+    BackingThreadHolder::instance().clear();
 }
 
-bool CompositorWorkerThread::hasIsolateForTest()
+void CompositorWorkerThread::resetSharedBackingThreadForTest()
 {
-    return CompositorWorkerSharedState::instance().hasIsolateForTest();
+    BackingThreadHolder::instance().resetForTest();
 }
 
 } // namespace blink