Add a mojo ServiceRegistry to embedded workers.

content/browser/service_worker/embedded_worker_instance.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/embedded_worker_instance.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind_helpers.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/trace_event/trace_event.h"
 #include "content/browser/devtools/service_worker_devtools_manager.h"
 #include "content/browser/service_worker/embedded_worker_registry.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/common/content_switches_internal.h"
+#include "content/common/mojo/service_registry_impl.h"
 #include "content/common/service_worker/embedded_worker_messages.h"
+#include "content/common/service_worker/embedded_worker_setup.mojom.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "ipc/ipc_message.h"
 #include "url/gurl.h"
 
 namespace content {
 
 namespace {
 
@@ skipping 47 matching lines @@
                 service_worker_context_weak,
                 service_worker_version_id,
                 url));
   }
   BrowserThread::PostTask(
       BrowserThread::IO,
       FROM_HERE,
       base::Bind(callback, worker_devtools_agent_route_id, wait_for_debugger));
 }
 
+void SetupMojoOnUIThread(int process_id,
+                         int thread_id,
+                         mojo::InterfaceRequest<mojo::ServiceProvider> services,
+                         mojo::ServiceProviderPtr exposed_services) {
+  RenderProcessHost* rph = RenderProcessHost::FromID(process_id);
+  // |rph| may be NULL in unit tests.
+  if (!rph)
+    return;
+  EmbeddedWorkerSetupPtr setup;
+  rph->GetServiceRegistry()->ConnectToRemoteService(mojo::GetProxy(&setup));
+  setup->ExchangeServiceProviders(thread_id, services.Pass(),

[michaeln, 2015/07/07 22:15:09]

I'm not familiar enough to know what happens at runtime but am curious.

How expensive is a connection to a remote service, what happens under the covers
here to establish the connection? Are these super liteweight? Is there a round
trip handshake that has to happen prior to remote service calls being sent?

And then once setup, when code on the IO thread invokes a method of a remote
service, what happens with regard to thread context switching? I'm wondering if
tasks get bounced to the UI thread first, then back to the IO thread for real
sending since the RPH's mojo registry service is tied to the UI thread? I have
the same questions about what happens on the remote side under the convers.

+                                  exposed_services.Pass());
+}
+
 }  // namespace
 
 // Lives on IO thread, proxies notifications to DevToolsManager that lives on
 // UI thread. Owned by EmbeddedWorkerInstance.
 class EmbeddedWorkerInstance::DevToolsProxy : public base::NonThreadSafe {
  public:
   DevToolsProxy(int process_id, int agent_route_id)
       : process_id_(process_id),
         agent_route_id_(agent_route_id) {}
 
@@ skipping 108 matching lines @@
 ServiceWorkerStatusCode EmbeddedWorkerInstance::SendMessage(
     const IPC::Message& message) {
   DCHECK_NE(kInvalidEmbeddedWorkerThreadId, thread_id_);
   if (status_ != RUNNING && status_ != STARTING)
     return SERVICE_WORKER_ERROR_IPC_FAILED;
   return registry_->Send(process_id_,
                          new EmbeddedWorkerContextMsg_MessageToWorker(
                              thread_id_, embedded_worker_id_, message));
 }
 
+ServiceRegistry* EmbeddedWorkerInstance::GetServiceRegistry() {
+  return service_registry_.get();
+}
+
 EmbeddedWorkerInstance::EmbeddedWorkerInstance(
     base::WeakPtr<ServiceWorkerContextCore> context,
     int embedded_worker_id)
     : context_(context),
       registry_(context->embedded_worker_registry()),
       embedded_worker_id_(embedded_worker_id),
       status_(STOPPED),
       starting_phase_(NOT_STARTING),
       process_id_(-1),
       thread_id_(kInvalidEmbeddedWorkerThreadId),
@@ skipping 122 matching lines @@
       UMA_HISTOGRAM_TIMES(
           "EmbeddedWorkerInstance.ScriptLoadWithoutNetworkAccess",
           base::TimeTicks::Now() - start_timing_);
     }
     // Reset |start_timing_| to measure the time excluding the process
     // allocation time and the script loading time.
     start_timing_ = base::TimeTicks::Now();
   }
   thread_id_ = thread_id;
   FOR_EACH_OBSERVER(Listener, listener_list_, OnScriptLoaded());
+
+  service_registry_.reset(new ServiceRegistryImpl());
+  mojo::ServiceProviderPtr exposed_services;
+  service_registry_->Bind(GetProxy(&exposed_services));
+  mojo::ServiceProviderPtr services;
+  mojo::InterfaceRequest<mojo::ServiceProvider> services_request =
+      GetProxy(&services);
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(SetupMojoOnUIThread, process_id_, thread_id_,
+                 base::Passed(&services_request),
+                 base::Passed(&exposed_services)));
+  service_registry_->BindRemoteServiceProvider(services.Pass());
 }
 
 void EmbeddedWorkerInstance::OnScriptLoadFailed() {
 }
 
 void EmbeddedWorkerInstance::OnScriptEvaluated(bool success) {
   starting_phase_ = SCRIPT_EVALUATED;
   if (start_callback_.is_null()) {
     DVLOG(1) << "Received unexpected OnScriptEvaluated message.";
     return;
@@ skipping 12 matching lines @@
   if (status_ == STOPPING)
     return;
   DCHECK(status_ == STARTING);
   status_ = RUNNING;
   FOR_EACH_OBSERVER(Listener, listener_list_, OnStarted());
 }
 
 void EmbeddedWorkerInstance::OnStopped() {
   Status old_status = status_;
   ReleaseProcess();
+  service_registry_.reset();
   FOR_EACH_OBSERVER(Listener, listener_list_, OnStopped(old_status));
 }
 
 void EmbeddedWorkerInstance::OnDetached() {
   Status old_status = status_;
   ReleaseProcess();
   FOR_EACH_OBSERVER(Listener, listener_list_, OnDetached(old_status));
 }
 
 void EmbeddedWorkerInstance::OnPausedAfterDownload() {
@@ skipping 105 matching lines @@
     case SCRIPT_EVALUATED:
       return "Script evaluated";
     case STARTING_PHASE_MAX_VALUE:
       NOTREACHED();
   }
   NOTREACHED() << phase;
   return std::string();
 }
 
 }  // namespace content