Bind Window focus ability to the ExecutionContext instead of the process.

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(const WebServiceWorkerClientInfo& info)
 {
     return new ServiceWorkerClient(info);
@@ skipping 44 matching lines @@
     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();
 
-    // FIXME: there should be a check for whether the caller is allowed to focus
-    // the client. The promise should succeed with |false| if the call is not
-    // allowed. https://crbug.com/437149
+    if (!scriptState->executionContext()->isWindowFocusAllowed()) {
+        resolver->resolve(false);
+        return promise;
+    }
+    scriptState->executionContext()->consumeWindowFocus();
 
     ServiceWorkerGlobalScopeClient::from(scriptState->executionContext())->focus(m_id, new CallbackPromiseAdapter<bool, ServiceWorkerError>(resolver));
     return promise;
 }
 
 } // namespace blink