[POC-WIP] Link window focus tokens with ExecutionContext.

Source/modules/serviceworkers/ServiceWorkerClient.cpp

 // Copyright 2014 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 "config.h"
 #include "modules/serviceworkers/ServiceWorkerClient.h"
 
+#include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/SerializedScriptValue.h"
+#include "core/page/WindowFocusAllowedIndicator.h"
+#include "modules/serviceworkers/ServiceWorkerError.h"
 #include "modules/serviceworkers/ServiceWorkerGlobalScopeClient.h"
 #include "public/platform/WebString.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 ServiceWorkerClient* ServiceWorkerClient::create(unsigned id)
 {
     return new ServiceWorkerClient(id);
 }
 
 ServiceWorkerClient::ServiceWorkerClient(unsigned id)
     : m_id(id)
 {
 }
 
 void ServiceWorkerClient::postMessage(ExecutionContext* context, PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
 {
     // Disentangle the port in preparation for sending it to the remote context.
     OwnPtr<MessagePortChannelArray> channels = MessagePort::disentanglePorts(ports, exceptionState);
     if (exceptionState.hadException())
         return;
 
     WebString messageString = message->toWireString();
     OwnPtr<WebMessagePortChannelArray> webChannels = MessagePort::toWebMessagePortChannelArray(channels.release());
     ServiceWorkerGlobalScopeClient::from(context)->postMessageToClient(m_id, messageString, webChannels.release());
 }
 
+ScriptPromise ServiceWorkerClient::focus(ScriptState* scriptState)
+{
+    RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+
+    if (!scriptState->executionContext()->isWindowFocusAllowed()) {
+        resolver->resolve(false);
+        return promise;
+    }
+    scriptState->executionContext()->consumeWindowFocusToken();
+
+    ServiceWorkerGlobalScopeClient::from(scriptState->executionContext())->focus(m_id, new CallbackPromiseAdapter<bool, ServiceWorkerError>(resolver));
+    return promise;
+}
+
 } // namespace blink