Introduce WorkerBackingThread

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

Index: third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThreadTest.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThreadTest.cpp b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThreadTest.cpp
index 32771eeb611e7d47d643709f3d59bb5e2e765fc4..534df2fa5eaa15d35f0bc0b47d5775489146ebd4 100644
--- a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThreadTest.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThreadTest.cpp
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/V8GCController.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/testing/DummyPageHolder.h"
+#include "core/workers/WorkerBackingThread.h"
 #include "core/workers/WorkerLoaderProxy.h"
 #include "core/workers/WorkerObjectProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
@@ -23,48 +24,6 @@
 namespace blink {
 namespace {
 
-class TestCompositorWorkerThread : public CompositorWorkerThread {
-public:
-    TestCompositorWorkerThread(WorkerLoaderProxyProvider* loaderProxyProvider, WorkerObjectProxy& objectProxy, double timeOrigin, WaitableEvent* startEvent)
-        : CompositorWorkerThread(WorkerLoaderProxy::create(loaderProxyProvider), objectProxy, timeOrigin)
-        , m_startEvent(startEvent)
-    {
-    }
-
-    ~TestCompositorWorkerThread() override {}
-
-    void setCallbackAfterV8Termination(PassOwnPtr<Function<void()>> callback)
-    {
-        m_v8TerminationCallback = callback;
-    }
-
-private:
-    // WorkerThread:
-    void didStartWorkerThread() override
-    {
-        m_startEvent->signal();
-    }
-
-    void terminateV8Execution() override
-    {
-        // This could be called on worker thread, but not in the test.
-        ASSERT(isMainThread());
-        CompositorWorkerThread::terminateV8Execution();
-        if (m_v8TerminationCallback)
-            (*m_v8TerminationCallback)();
-    }
-
-    void willDestroyIsolate() override
-    {
-        v8::Isolate::GetCurrent()->RequestGarbageCollectionForTesting(v8::Isolate::kFullGarbageCollection);
-        Heap::collectAllGarbage();
-        CompositorWorkerThread::willDestroyIsolate();
-    }
-
-    WaitableEvent* m_startEvent;
-    OwnPtr<Function<void()>> m_v8TerminationCallback;
-};
-
 // A null WorkerObjectProxy, supplied when creating CompositorWorkerThreads.
 class TestCompositorWorkerObjectProxy : public WorkerObjectProxy {
 public:
@@ -122,6 +81,7 @@ class CompositorWorkerThreadTest : public ::testing::Test {
 public:
     void SetUp() override
     {
+        CompositorWorkerThread::resetSharedBackingThreadForTest();
         m_page = DummyPageHolder::create();
         m_objectProxy = TestCompositorWorkerObjectProxy::create(&m_page->document());
         m_securityOrigin = SecurityOrigin::create(KURL(ParsedURLString, "http://fake.url/"));
@@ -129,14 +89,13 @@ public:
 
     void TearDown() override
     {
-        ASSERT(!hasThread());
-        ASSERT(!hasIsolate());
         m_page.clear();
+        CompositorWorkerThread::resetSharedBackingThreadForTest();
     }
 
-    PassOwnPtr<TestCompositorWorkerThread> createCompositorWorker(WaitableEvent* startEvent)
+    PassOwnPtr<CompositorWorkerThread> createCompositorWorker()
     {
-        TestCompositorWorkerThread* workerThread = new TestCompositorWorkerThread(nullptr, *m_objectProxy, 0, startEvent);
+        OwnPtr<CompositorWorkerThread> workerThread = CompositorWorkerThread::create(nullptr, *m_objectProxy, 0);
         WorkerClients* clients = nullptr;
         workerThread->start(WorkerThreadStartupData::create(
             KURL(ParsedURLString, "http://fake.url/"),
@@ -149,42 +108,22 @@ public:
             clients,
             WebAddressSpaceLocal,
             V8CacheOptionsDefault));
-        return adoptPtr(workerThread);
-    }
-
-    void createWorkerAdapter(OwnPtr<CompositorWorkerThread>* workerThread, WaitableEvent* creationEvent)
-    {
-        *workerThread = createCompositorWorker(creationEvent);
+        return workerThread.release();
     }
 
     // Attempts to run some simple script for |worker|.
     void checkWorkerCanExecuteScript(WorkerThread* worker)
     {
         OwnPtr<WaitableEvent> waitEvent = adoptPtr(new WaitableEvent());
-        worker->backingThread().platformThread().getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&CompositorWorkerThreadTest::executeScriptInWorker, AllowCrossThreadAccess(this),
+        worker->workerBackingThread().backingThread().postTask(BLINK_FROM_HERE, threadSafeBind(&CompositorWorkerThreadTest::executeScriptInWorker, AllowCrossThreadAccess(this),
             AllowCrossThreadAccess(worker), AllowCrossThreadAccess(waitEvent.get())));
         waitEvent->wait();
     }
 
-    void waitForWaitableEventAfterIteratingCurrentLoop(WaitableEvent* waitEvent)
-    {
-        testing::runPendingTasks();
-        waitEvent->wait();
-    }
-
-    bool hasThread() const
-    {
-        return CompositorWorkerThread::hasThreadForTest();
-    }
-
-    bool hasIsolate() const
-    {
-        return CompositorWorkerThread::hasIsolateForTest();
-    }
-
 private:
     void executeScriptInWorker(WorkerThread* worker, WaitableEvent* waitEvent)
     {
+        EXPECT_GT(worker->workerBackingThread().workerScriptCount(), 0u);
         WorkerOrWorkletScriptController* scriptController = worker->workerGlobalScope()->scriptController();
         bool evaluateResult = scriptController->evaluate(ScriptSourceCode("var counter = 0; ++counter;"));
         ASSERT_UNUSED(evaluateResult, evaluateResult);
@@ -199,9 +138,7 @@ private:
 
 TEST_F(CompositorWorkerThreadTest, Basic)
 {
-    OwnPtr<WaitableEvent> creationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<CompositorWorkerThread> compositorWorker = createCompositorWorker(creationEvent.get());
-    waitForWaitableEventAfterIteratingCurrentLoop(creationEvent.get());
+    OwnPtr<CompositorWorkerThread> compositorWorker = createCompositorWorker();
     checkWorkerCanExecuteScript(compositorWorker.get());
     compositorWorker->terminateAndWait();
 }
@@ -210,28 +147,23 @@ TEST_F(CompositorWorkerThreadTest, Basic)
 TEST_F(CompositorWorkerThreadTest, CreateSecondAndTerminateFirst)
 {
     // Create the first worker and wait until it is initialized.
-    OwnPtr<WaitableEvent> firstCreationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<CompositorWorkerThread> firstWorker = createCompositorWorker(firstCreationEvent.get());
-    WebThreadSupportingGC* firstThread = CompositorWorkerThread::sharedBackingThread();
-    ASSERT(firstThread);
-    waitForWaitableEventAfterIteratingCurrentLoop(firstCreationEvent.get());
+    OwnPtr<CompositorWorkerThread> firstWorker = createCompositorWorker();
+    WebThreadSupportingGC* firstThread = &firstWorker->workerBackingThread().backingThread();
+    checkWorkerCanExecuteScript(firstWorker.get());
     v8::Isolate* firstIsolate = firstWorker->isolate();
-    ASSERT(firstIsolate);
+    ASSERT_TRUE(firstIsolate);
 
     // Create the second worker and immediately destroy the first worker.
-    OwnPtr<WaitableEvent> secondCreationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<CompositorWorkerThread> secondWorker = createCompositorWorker(secondCreationEvent.get());
+    OwnPtr<CompositorWorkerThread> secondWorker = createCompositorWorker();
     firstWorker->terminateAndWait();
 
     // Wait until the second worker is initialized. Verify that the second worker is using the same
     // thread and Isolate as the first worker.
-    WebThreadSupportingGC* secondThread = CompositorWorkerThread::sharedBackingThread();
-    ASSERT(secondThread);
-    waitForWaitableEventAfterIteratingCurrentLoop(secondCreationEvent.get());
-    EXPECT_EQ(firstThread, secondThread);
+    WebThreadSupportingGC* secondThread = &secondWorker->workerBackingThread().backingThread();
+    ASSERT_EQ(firstThread, secondThread);
 
     v8::Isolate* secondIsolate = secondWorker->isolate();
-    ASSERT(secondIsolate);
+    ASSERT_TRUE(secondIsolate);
     EXPECT_EQ(firstIsolate, secondIsolate);
 
     // Verify that the worker can still successfully execute script.
@@ -240,36 +172,26 @@ TEST_F(CompositorWorkerThreadTest, CreateSecondAndTerminateFirst)
     secondWorker->terminateAndWait();
 }
 
-static void checkCurrentIsolate(v8::Isolate* isolate, WaitableEvent* event)
-{
-    EXPECT_EQ(v8::Isolate::GetCurrent(), isolate);
-    event->signal();
-}
-
 // Tests that a new WebThread is created if all existing workers are terminated before a new worker is created.
 TEST_F(CompositorWorkerThreadTest, TerminateFirstAndCreateSecond)
 {
     // Create the first worker, wait until it is initialized, and terminate it.
-    OwnPtr<WaitableEvent> creationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<CompositorWorkerThread> compositorWorker = createCompositorWorker(creationEvent.get());
-    WebThreadSupportingGC* firstThread = CompositorWorkerThread::sharedBackingThread();
-    waitForWaitableEventAfterIteratingCurrentLoop(creationEvent.get());
-    ASSERT(compositorWorker->isolate());
+    OwnPtr<CompositorWorkerThread> compositorWorker = createCompositorWorker();
+    WorkerBackingThread* workerBackingThread = &compositorWorker->workerBackingThread();
+    WebThreadSupportingGC* firstThread = &compositorWorker->workerBackingThread().backingThread();
+    checkWorkerCanExecuteScript(compositorWorker.get());
+
+    ASSERT_EQ(1u, workerBackingThread->workerScriptCount());
     compositorWorker->terminateAndWait();
 
-    // Create the second worker. Verify that the second worker lives in a different WebThread since the first
-    // thread will have been destroyed after destroying the first worker.
-    creationEvent = adoptPtr(new WaitableEvent());
-    compositorWorker = createCompositorWorker(creationEvent.get());
-    WebThreadSupportingGC* secondThread = CompositorWorkerThread::sharedBackingThread();
-    EXPECT_NE(firstThread, secondThread);
-    waitForWaitableEventAfterIteratingCurrentLoop(creationEvent.get());
-
-    // Jump over to the worker's thread to verify that the Isolate is set up correctly and execute script.
-    OwnPtr<WaitableEvent> checkEvent = adoptPtr(new WaitableEvent());
-    secondThread->platformThread().getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&checkCurrentIsolate, AllowCrossThreadAccess(compositorWorker->isolate()), AllowCrossThreadAccess(checkEvent.get())));
-    waitForWaitableEventAfterIteratingCurrentLoop(checkEvent.get());
+    ASSERT_EQ(0u, workerBackingThread->workerScriptCount());
+
+    // Create the second worker. The backing thread is same.
+    compositorWorker = createCompositorWorker();
+    WebThreadSupportingGC* secondThread = &compositorWorker->workerBackingThread().backingThread();
+    EXPECT_EQ(firstThread, secondThread);
     checkWorkerCanExecuteScript(compositorWorker.get());
+    ASSERT_EQ(1u, workerBackingThread->workerScriptCount());
 
     compositorWorker->terminateAndWait();
 }
@@ -277,23 +199,23 @@ TEST_F(CompositorWorkerThreadTest, TerminateFirstAndCreateSecond)
 // Tests that v8::Isolate and WebThread are correctly set-up if a worker is created while another is terminating.
 TEST_F(CompositorWorkerThreadTest, CreatingSecondDuringTerminationOfFirst)
 {
-    OwnPtr<WaitableEvent> firstCreationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<TestCompositorWorkerThread> firstWorker = createCompositorWorker(firstCreationEvent.get());
-    waitForWaitableEventAfterIteratingCurrentLoop(firstCreationEvent.get());
+    OwnPtr<CompositorWorkerThread> firstWorker = createCompositorWorker();
+    checkWorkerCanExecuteScript(firstWorker.get());
     v8::Isolate* firstIsolate = firstWorker->isolate();
-    ASSERT(firstIsolate);
+    ASSERT_TRUE(firstIsolate);
 
-    // Request termination of the first worker, and set-up to make sure the second worker is created right as
-    // the first worker terminates its isolate.
-    OwnPtr<WaitableEvent> secondCreationEvent = adoptPtr(new WaitableEvent());
-    OwnPtr<CompositorWorkerThread> secondWorker;
-    firstWorker->setCallbackAfterV8Termination(bind(&CompositorWorkerThreadTest::createWorkerAdapter, this, &secondWorker, secondCreationEvent.get()));
-    firstWorker->terminateAndWait();
-    ASSERT(secondWorker);
+    // Request termination of the first worker and create the second worker
+    // as soon as possible.
+    EXPECT_EQ(1u, firstWorker->workerBackingThread().workerScriptCount());
+    firstWorker->terminate();
+    // We don't wait for its termination.
+    // Note: We rely on the assumption that the termination steps don't run
+    // on the worker thread so quickly. This could be a source of flakiness.
+
+    OwnPtr<CompositorWorkerThread> secondWorker = createCompositorWorker();
 
-    waitForWaitableEventAfterIteratingCurrentLoop(secondCreationEvent.get());
     v8::Isolate* secondIsolate = secondWorker->isolate();
-    ASSERT(secondIsolate);
+    ASSERT_TRUE(secondIsolate);
     EXPECT_EQ(firstIsolate, secondIsolate);
 
     // Verify that the isolate can run some scripts correctly in the second worker.