Bug 196825

After r244182, RemoteLayerTreeDrawingArea::flushLayers() can be reentrant when running run-webkit-tests. This can happen when notifyDone() is called from the rAF callback which forces repaint. Here is the problematic call stack: 3 0x1033b3acd WebKit::RemoteLayerTreeDrawingArea::flushLayers() 4 0x1033b64be WebKit::RemoteLayerTreeDrawingArea::forceRepaint() 5 0x104462f85 WebKit::WebPage::forceRepaintWithoutCallback() 6 0x10413ddbd WKBundlePageForceRepaint 7 0x4ec12346e WTR::InjectedBundlePage::dump() 8 0x4ec146afd WTR::TestRunner::notifyDone() 9 0x4ec1390a7 WTR::JSTestRunner::notifyDone(OpaqueJSContext const*, OpaqueJSValue*, OpaqueJSValue*, unsigned long, OpaqueJSValue const* const*, OpaqueJSValue const**) 10 0x4cb554d51 long long JSC::APICallbackFunction::call<JSC::JSCallbackFunction>(JSC::ExecState*) 11 0x23a354601027 12 0x4cb4d18b1 llint_entry 13 0x4cb4d18b1 llint_entry 14 0x4cb4d18b1 llint_entry 15 0x4cb4be500 vmEntryToJavaScript 16 0x4cbe3dace JSC::JITCode::execute(JSC::VM*, JSC::ProtoCallFrame*) 17 0x4cbe3e0ff JSC::Interpreter::executeCall(JSC::ExecState*, JSC::JSObject*, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) 18 0x4cc115c4c JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) 19 0x4cc115d3a JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&, WTF::NakedPtr<JSC::Exception>&) 20 0x4cc11602e JSC::profiledCall(JSC::ExecState*, JSC::ProfilingReason, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&, WTF::NakedPtr<JSC::Exception>&) 21 0x4d0ec3fdb WebCore::JSExecState::profiledCall(JSC::ExecState*, JSC::ProfilingReason, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&, WTF::NakedPtr<JSC::Exception>&) 22 0x4d0ec3e8f WebCore::JSCallbackData::invokeCallback(WebCore::JSDOMGlobalObject&, JSC::JSObject*, JSC::JSValue, JSC::MarkedArgumentBuffer&, WebCore::JSCallbackData::CallbackType, JSC::PropertyName, WTF::NakedPtr<JSC::Exception>&) 23 0x4cf65d332 WebCore::JSCallbackDataStrong::invokeCallback(JSC::JSValue, JSC::MarkedArgumentBuffer&, WebCore::JSCallbackData::CallbackType, JSC::PropertyName, WTF::NakedPtr<JSC::Exception>&) 24 0x4d020deb9 WebCore::JSRequestAnimationFrameCallback::handleEvent(double) 25 0x4d15d8344 WebCore::ScriptedAnimationController::serviceRequestAnimationFrameCallbacks(double) 26 0x4d14180d6 WebCore::Document::serviceRequestAnimationFrameCallbacks(double) 27 0x4d1f29387 WebCore::Page::updateRendering() 28 0x1044642d4 WebKit::WebPage::updateRendering() 29 0x1033b3ae9 WebKit::RemoteLayerTreeDrawingArea::flushLayers() 30 0x1033bcf91 WTF::Function<void ()>::CallableWrapper<std::__1::__bind<void (WebKit::RemoteLayerTreeDrawingArea::*&)(), WebKit::RemoteLayerTreeDrawingArea*> >::call() 31 0x1032f665d WTF::Function<void ()>::operator()() const This call stack was caught by the iOS simulator layout tests because RemoteLayerTreeDrawingAreaProxy::commitLayerTree() asserts the transition IDs are sequential.