[ServiceWorker] Fix thread jumping race condition in SWProviderHost.

content/browser/service_worker/service_worker_provider_host.cc

 // Copyright 2013 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 "content/browser/service_worker/service_worker_provider_host.h"
 
 #include "base/stl_util.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
@@ skipping 12 matching lines @@
 #include "content/common/service_worker/service_worker_types.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/child_process_host.h"
 
 namespace content {
 
 namespace {
 
-void GetClientInfoOnUIThread(
+ServiceWorkerClientInfo GetClientInfoOnUIThread(
     int render_process_id,
-    int render_frame_id,
-    const ServiceWorkerProviderHost::GetClientInfoCallback& callback) {
+    int render_frame_id) {
   RenderFrameHostImpl* render_frame_host =
       RenderFrameHostImpl::FromID(render_process_id, render_frame_id);
-  if (!render_frame_host) {
-    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-                            base::Bind(callback, ServiceWorkerClientInfo()));
-    return;
-  }
+  if (!render_frame_host)
+    return ServiceWorkerClientInfo();
 
   // TODO(mlamouri,michaeln): it is possible to end up collecting information
   // for a frame that is actually being navigated and isn't exactly what we are
   // expecting.
-  ServiceWorkerClientInfo client_info(
+  return ServiceWorkerClientInfo(
       render_frame_host->GetVisibilityState(),
       render_frame_host->IsFocused(),
       render_frame_host->GetLastCommittedURL(),
       render_frame_host->GetParent() ? REQUEST_CONTEXT_FRAME_TYPE_NESTED
                                      : REQUEST_CONTEXT_FRAME_TYPE_TOP_LEVEL);
-
-  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-                          base::Bind(callback, client_info));
 }
 
-void FocusOnUIThread(
+ServiceWorkerClientInfo FocusOnUIThread(
     int render_process_id,
-    int render_frame_id,
-    const ServiceWorkerProviderHost::GetClientInfoCallback& callback) {
+    int render_frame_id) {
   RenderFrameHostImpl* render_frame_host =
       RenderFrameHostImpl::FromID(render_process_id, render_frame_id);
   WebContentsImpl* web_contents = static_cast<WebContentsImpl*>(
       WebContents::FromRenderFrameHost(render_frame_host));
 
-  if (!render_frame_host || !web_contents) {
-    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-                            base::Bind(callback, ServiceWorkerClientInfo()));
-    return;
-  }
+  if (!render_frame_host || !web_contents)
+    return ServiceWorkerClientInfo();
 
   FrameTreeNode* frame_tree_node = render_frame_host->frame_tree_node();
 
   // Focus the frame in the frame tree node, in case it has changed.
   frame_tree_node->frame_tree()->SetFocusedFrame(frame_tree_node);
 
   // Focus the frame's view to make sure the frame is now considered as focused.
   render_frame_host->GetView()->Focus();
 
   // Move the web contents to the foreground.
   web_contents->Activate();
 
-  GetClientInfoOnUIThread(render_process_id, render_frame_id, callback);
+  return GetClientInfoOnUIThread(render_process_id, render_frame_id);
 }
 
 }  // anonymous namespace
 
 ServiceWorkerProviderHost::ServiceWorkerProviderHost(
     int render_process_id,
     int render_frame_id,
     int provider_id,
     base::WeakPtr<ServiceWorkerContextCore> context,
     ServiceWorkerDispatcherHost* dispatcher_host)
@@ skipping 198 matching lines @@
                                       &new_routing_ids);
 
   Send(new ServiceWorkerMsg_MessageToDocument(
       kDocumentMainThreadId, provider_id(),
       message,
       sent_message_port_ids,
       new_routing_ids));
 }
 
 void ServiceWorkerProviderHost::Focus(const GetClientInfoCallback& callback) {
-  BrowserThread::PostTask(
+  BrowserThread::PostTaskAndReplyWithResult(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&FocusOnUIThread,
                  render_process_id_,
-                 render_frame_id_,
-                 callback));
+                 render_frame_id_),
+      callback);
 }
 
 void ServiceWorkerProviderHost::GetClientInfo(
     const GetClientInfoCallback& callback) const {
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&GetClientInfoOnUIThread,
-                                     render_process_id_,
-                                     render_frame_id_,
-                                     callback));
+  BrowserThread::PostTaskAndReplyWithResult(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&GetClientInfoOnUIThread,
+                render_process_id_,
+                render_frame_id_),
+      callback);
 }
 
 void ServiceWorkerProviderHost::AddScopedProcessReferenceToPattern(
     const GURL& pattern) {
   associated_patterns_.push_back(pattern);
   IncreaseProcessReference(pattern);
 }
 
 void ServiceWorkerProviderHost::ClaimedByRegistration(
     ServiceWorkerRegistration* registration) {
@@ skipping 184 matching lines @@
   return context_ != NULL;
 }
 
 void ServiceWorkerProviderHost::Send(IPC::Message* message) const {
   DCHECK(dispatcher_host_);
   DCHECK(IsReadyToSendMessages());
   dispatcher_host_->Send(message);
 }
 
 }  // namespace content