ServiceWorker: add ServiceWorkerClients.claim() support (1/3).

public/web/WebServiceWorkerContextClient.h

Index: public/web/WebServiceWorkerContextClient.h
diff --git a/public/web/WebServiceWorkerContextClient.h b/public/web/WebServiceWorkerContextClient.h
index 9e1ceb5c2d847cc5307c123402734e92ba21328c..86c74b2e80c9133b942f007131344b029dac8355 100644
--- a/public/web/WebServiceWorkerContextClient.h
+++ b/public/web/WebServiceWorkerContextClient.h
@@ -34,6 +34,7 @@
 #include "WebWorkerPermissionClientProxy.h"
 #include "public/platform/WebMessagePortChannel.h"
 #include "public/platform/WebServiceWorkerClientFocusCallback.h"
+#include "public/platform/WebServiceWorkerClientsClaimCallbacks.h"
 #include "public/platform/WebServiceWorkerClientsInfo.h"
 #include "public/platform/WebServiceWorkerEventResult.h"
 #include "public/platform/WebServiceWorkerSkipWaitingCallbacks.h"
@@ -167,6 +168,10 @@ public:
     virtual void skipWaiting(WebServiceWorkerSkipWaitingCallbacks*) { BLINK_ASSERT_NOT_REACHED(); }
 
     // Ownership of the passed callbacks is transferred to the callee, callee
+    // should delete the callbacks after run.
+    virtual void claim(WebServiceWorkerClientsClaimCallbacks*) { BLINK_ASSERT_NOT_REACHED(); }
+
+    // Ownership of the passed callbacks is transferred to the callee, callee
     // should delete the callback after calling either onSuccess or onError.
     virtual void focus(int clientID, WebServiceWorkerClientFocusCallback* callback)
     {