Added lifecycle management and sharing support for SharedWorkers. SharedWorkers

chrome/worker/websharedworker_stub.cc

 // Copyright (c) 2009 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 "chrome/worker/websharedworker_stub.h"
 
 #include "chrome/common/webmessageportchannel_impl.h"
 #include "chrome/common/worker_messages.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebSharedWorker.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebString.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebURL.h"
 
 WebSharedWorkerStub::WebSharedWorkerStub(
     const string16& name, int route_id)
     : WebWorkerStubBase(route_id),
-      name_(name) {
+      name_(name),
+      started_(false) {
 
   // TODO(atwilson): Add support for NaCl when they support MessagePorts.
   impl_ = WebKit::WebSharedWorker::create(client());
 
 }
 
 WebSharedWorkerStub::~WebSharedWorkerStub() {
   impl_->clientDestroyed();
 }
 
 void WebSharedWorkerStub::OnMessageReceived(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(WebSharedWorkerStub, message)
     IPC_MESSAGE_HANDLER(WorkerMsg_StartWorkerContext, OnStartWorkerContext)
     IPC_MESSAGE_HANDLER(WorkerMsg_TerminateWorkerContext,
                         OnTerminateWorkerContext)
     IPC_MESSAGE_HANDLER(WorkerMsg_Connect, OnConnect)
   IPC_END_MESSAGE_MAP()
 }
 
 void WebSharedWorkerStub::OnStartWorkerContext(
     const GURL& url, const string16& user_agent, const string16& source_code) {
+  // Ignore multiple attempts to start this worker (can happen if two pages
+  // try to start it simultaneously).
+  if (started_)
+    return;
   impl_->startWorkerContext(url, name_, user_agent, source_code);
+  started_ = true;
 }
 
 void WebSharedWorkerStub::OnConnect(int sent_message_port_id, int routing_id) {
+  DCHECK(started_);
   WebKit::WebMessagePortChannel* channel =
       new WebMessagePortChannelImpl(routing_id, sent_message_port_id);
   impl_->connect(channel, NULL);
 }
 
 void WebSharedWorkerStub::OnTerminateWorkerContext() {
   impl_->terminateWorkerContext();
 
   // Call the client to make sure context exits.
   EnsureWorkerContextTerminates();
+  started_ = false;
 }