compositor-worker: Initialize CW machinery plumbing to compositor and fire CW rAF callbacks.

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..31dfb0e58b85fb4a6471517bc8892b99f0ebd28b 100644
--- a/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp
@@ -11,6 +11,7 @@
 #include "bindings/core/v8/V8PerIsolateData.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ThreadSafeFunctional.h"
+#include "platform/WaitableEvent.h"
 #include "platform/WebThreadSupportingGC.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebTraceLocation.h"
@@ -57,10 +58,13 @@ WorkerBackingThread::WorkerBackingThread(WebThread* thread, bool shouldCallGCOnS
     , m_isOwningThread(false)
     , m_shouldCallGCOnShutdown(shouldCallGCOnShutdown)
 {
+    thread->getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&WorkerBackingThread::initialize, AllowCrossThreadAccess(this)));
 }
 
 WorkerBackingThread::~WorkerBackingThread()
 {
+    if (!m_isOwningThread)
+        signalShutdownAndWait();
 #if DCHECK_IS_ON()
     MutexLocker locker(m_mutex);
     DCHECK_EQ(0u, m_workerScriptCount);
@@ -74,7 +78,8 @@ void WorkerBackingThread::attach()
         if (++m_workerScriptCount > 1)
             return;
     }
-    initialize();
+    if (m_isOwningThread)
+        initialize();
 }
 
 void WorkerBackingThread::detach()
@@ -84,7 +89,8 @@ void WorkerBackingThread::detach()
         if (--m_workerScriptCount > 0)
             return;
     }
-    shutdown();
+    if (m_isOwningThread)
+        shutdown();
 }
 
 void WorkerBackingThread::initialize()
@@ -104,7 +110,7 @@ void WorkerBackingThread::initialize()
         Platform::current()->didStartWorkerThread();
 }
 
-void WorkerBackingThread::shutdown()
+void WorkerBackingThread::shutdown(WaitableEvent* doneEvent)
 {
     if (m_isOwningThread)
         Platform::current()->willStopWorkerThread();
@@ -120,6 +126,15 @@ void WorkerBackingThread::shutdown()
     V8PerIsolateData::destroy(m_isolate);
     removeWorkerIsolate(m_isolate);
     m_isolate = nullptr;
+    if (doneEvent)
+        doneEvent->signal();
+}
+
+void WorkerBackingThread::signalShutdownAndWait()
+{
+    WaitableEvent doneEvent;
+    m_backingThread->platformThread().getWebTaskRunner()->postTask(BLINK_FROM_HERE, threadSafeBind(&WorkerBackingThread::shutdown, AllowCrossThreadAccess(this), AllowCrossThreadAccess(&doneEvent)));
+    doneEvent.wait();
 }
 
 // static