Use UUID for ServiceWorker Client identifier (1/3, blink)

Source/modules/serviceworkers/ServiceWorkerClient.cpp

Index: Source/modules/serviceworkers/ServiceWorkerClient.cpp
diff --git a/Source/modules/serviceworkers/ServiceWorkerClient.cpp b/Source/modules/serviceworkers/ServiceWorkerClient.cpp
index 4ee82cac8eb8960e6cf6b4ad4c3d25af3d038a2a..109f50fb943abfe7396fcd7c8bb2df533a887be8 100644
--- a/Source/modules/serviceworkers/ServiceWorkerClient.cpp
+++ b/Source/modules/serviceworkers/ServiceWorkerClient.cpp
@@ -21,6 +21,7 @@ ServiceWorkerClient* ServiceWorkerClient::create(const WebServiceWorkerClientInf
 
 ServiceWorkerClient::ServiceWorkerClient(const WebServiceWorkerClientInfo& info)
     : m_id(info.clientID)
+    , m_uuid(info.uuid)
     , m_url(info.url.string())
 {
 }
@@ -38,7 +39,12 @@ void ServiceWorkerClient::postMessage(ExecutionContext* context, PassRefPtr<Seri
 
     WebString messageString = message->toWireString();
     OwnPtr<WebMessagePortChannelArray> webChannels = MessagePort::toWebMessagePortChannelArray(channels.release());
-    ServiceWorkerGlobalScopeClient::from(context)->postMessageToClient(m_id, messageString, webChannels.release());
+    if (!m_uuid.isEmpty()) {
+        ServiceWorkerGlobalScopeClient::from(context)->postMessageToClient(m_uuid, messageString, webChannels.release());
+    } else {
+        // FIXME: Deprecate this when we switch to uuid.
+        ServiceWorkerGlobalScopeClient::from(context)->postMessageToClient(m_id, messageString, webChannels.release());
+    }
 }
 
 } // namespace blink