PlzNavigate: implement process reuse for ServiceWorkers

content/browser/service_worker/service_worker_process_manager.cc

 // Copyright 2014 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_process_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/common/service_worker/embedded_worker_settings.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/child_process_host.h"
 #include "content/public/common/content_client.h"
 #include "url/gurl.h"
 
 namespace content {
 
@@ skipping 185 matching lines @@
           std::make_pair(embedded_worker_id, ProcessInfo(process_id)));
       BrowserThread::PostTask(
           BrowserThread::IO, FROM_HERE,
           base::Bind(callback, SERVICE_WORKER_OK, process_id,
                      false /* is_new_process */, settings));
       return;
     }
   }
 
   // No existing processes available; start a new one.
-  scoped_refptr<SiteInstance> site_instance =
-      SiteInstance::CreateForURL(browser_context_, script_url);
+  scoped_refptr<SiteInstanceImpl> site_instance =
+      SiteInstanceImpl::CreateForURL(browser_context_, script_url);
+  site_instance->set_process_reuse_policy(
+      SiteInstanceImpl::ProcessReusePolicy::
+          REUSE_CHECKING_FRAMES_AND_NAVIGATIONS);

[nasko, 2017/05/05 05:22:00]

Reading this code, I wonder if it will be more natural to pass the policy as
parameter to GetProcess() and it can set it internally.

[clamy, 2017/05/05 15:10:11]

Except it could have already been set in other cases before we get to
GetProcess.

Maybe we could have GetProcessWithReusePolicy(policy) that sets the policy then
does GetProcess?

[Charlie Reis, 2017/05/15 03:41:52]

Just curious, what's the advantage of either of these approaches?  I think
having a separate set_process_reuse_policy seems ok.

[clamy, 2017/05/16 14:50:46]

I'm leaving it as is for now.

   RenderProcessHost* rph = site_instance->GetProcess();
 
   // This Init() call posts a task to the IO thread that adds the RPH's
   // ServiceWorkerDispatcherHost to the
   // EmbeddedWorkerRegistry::process_sender_map_.
   if (!rph->Init()) {
     LOG(ERROR) << "Couldn't start a new process!";
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(callback, SERVICE_WORKER_ERROR_PROCESS_NOT_FOUND,
@@ skipping 108 matching lines @@
 namespace std {
 // Destroying ServiceWorkerProcessManagers only on the UI thread allows the
 // member WeakPtr to safely guard the object's lifetime when used on that
 // thread.
 void default_delete<content::ServiceWorkerProcessManager>::operator()(
     content::ServiceWorkerProcessManager* ptr) const {
   content::BrowserThread::DeleteSoon(
       content::BrowserThread::UI, FROM_HERE, ptr);
 }
 }  // namespace std