Initialize app_cache_host_ of EmbeddedSharedWorkerStub.

content/renderer/shared_worker/embedded_shared_worker_stub.cc

Index: content/renderer/shared_worker/embedded_shared_worker_stub.cc
diff --git a/content/renderer/shared_worker/embedded_shared_worker_stub.cc b/content/renderer/shared_worker/embedded_shared_worker_stub.cc
index eeb601c279667f4b475a932eb27d55373a5c70d5..fbfb7070de4d7b3a4148058f8fb3ae77ca45ded4 100644
--- a/content/renderer/shared_worker/embedded_shared_worker_stub.cc
+++ b/content/renderer/shared_worker/embedded_shared_worker_stub.cc
@@ -61,7 +61,11 @@ EmbeddedSharedWorkerStub::EmbeddedSharedWorkerStub(
     blink::WebContentSecurityPolicyType security_policy_type,
     bool pause_on_start,
     int route_id)
-    : route_id_(route_id), name_(name), runing_(false), url_(url) {
+    : route_id_(route_id),
+      name_(name),
+      runing_(false),
+      url_(url),
+      app_cache_host_(nullptr) {
   RenderThreadImpl::current()->AddEmbeddedWorkerRoute(route_id_, this);
   impl_ = blink::WebSharedWorker::create(this);
   if (pause_on_start) {