Forcibly clear worker ref counts on shutdown.

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 2012 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 657 matching lines @@
     bool is_for_guests_only)
     : fast_shutdown_started_(false),
       deleting_soon_(false),
 #ifndef NDEBUG
       is_self_deleted_(false),
 #endif
       pending_views_(0),
       child_token_(mojo::edk::GenerateRandomToken()),
       service_worker_ref_count_(0),
       shared_worker_ref_count_(0),
+      is_worker_ref_count_disabled_(false),
       visible_widgets_(0),
       is_process_backgrounded_(false),
       is_initialized_(false),
       id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()),
       browser_context_(browser_context),
       storage_partition_impl_(storage_partition_impl),
       sudden_termination_allowed_(true),
       ignore_input_events_(false),
       is_for_guests_only_(is_for_guests_only),
       gpu_observer_registered_(false),
@@ skipping 646 matching lines @@
   return manager->GetCdm(render_frame_id, cdm_id);
 }
 #endif
 
 bool RenderProcessHostImpl::IsProcessBackgrounded() const {
   return is_process_backgrounded_;
 }
 
 void RenderProcessHostImpl::IncrementServiceWorkerRefCount() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(!is_worker_ref_count_disabled_);
   ++service_worker_ref_count_;
   if (worker_ref_count() > max_worker_count_)
     max_worker_count_ = worker_ref_count();
 }
 
 void RenderProcessHostImpl::DecrementServiceWorkerRefCount() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK_GT(worker_ref_count(), 0UL);
+  DCHECK(!is_worker_ref_count_disabled_);
+  DCHECK_GT(worker_ref_count(), 0U);
   --service_worker_ref_count_;
   if (worker_ref_count() == 0)
     Cleanup();
 }
 
 void RenderProcessHostImpl::IncrementSharedWorkerRefCount() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(!is_worker_ref_count_disabled_);
   ++shared_worker_ref_count_;
   if (worker_ref_count() > max_worker_count_)
     max_worker_count_ = worker_ref_count();
 }
 
 void RenderProcessHostImpl::DecrementSharedWorkerRefCount() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK_GT(worker_ref_count(), 0UL);
+  DCHECK(!is_worker_ref_count_disabled_);
+  DCHECK_GT(worker_ref_count(), 0U);
   --shared_worker_ref_count_;
   if (worker_ref_count() == 0)
     Cleanup();
 }
 
+void RenderProcessHostImpl::ForceReleaseWorkerRefCounts() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  is_worker_ref_count_disabled_ = true;

[jam, 2016/09/14 17:10:49]

DCHECK(!is_worker_ref_count_disabled_); before this?

[falken, 2016/09/21 08:59:43]

Done.

+  if (!worker_ref_count())
+    return;
+  service_worker_ref_count_ = 0;
+  shared_worker_ref_count_ = 0;
+  Cleanup();
+}
+
+bool RenderProcessHostImpl::IsWorkerRefCountDisabled() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  return is_worker_ref_count_disabled_;
+}
+
 void RenderProcessHostImpl::PurgeAndSuspend() {
   Send(new ChildProcessMsg_PurgeAndSuspend());
 }
 
 void RenderProcessHostImpl::AddRoute(int32_t routing_id,
                                      IPC::Listener* listener) {
   CHECK(!listeners_.Lookup(routing_id)) << "Found Routing ID Conflict: "
                                         << routing_id;
   listeners_.AddWithID(listener, routing_id);
 }
@@ skipping 482 matching lines @@
     return false;  // Render process hasn't started or is probably crashed.
 
   // Test if there's an unload listener.
   // NOTE: It's possible that an onunload listener may be installed
   // while we're shutting down, so there's a small race here.  Given that
   // the window is small, it's unlikely that the web page has much
   // state that will be lost by not calling its unload handlers properly.
   if (!SuddenTerminationAllowed())
     return false;
 
   if (worker_ref_count() != 0) {

[alokp, 2016/09/16 04:47:53]

should we still prevent fast shutdown for worker_ref_count > 0?

[falken, 2016/09/21 08:59:43]

I think we still need to because fast shutdown won't necessarily lead to browser
shutdown. Other processes with unload handlers may be depending on a worker in
this process.

     if (survive_for_worker_start_time_.is_null())
       survive_for_worker_start_time_ = base::TimeTicks::Now();
     return false;
   }
 
   // Set this before ProcessDied() so observers can tell if the render process
   // died due to fast shutdown versus another cause.
   fast_shutdown_started_ = true;
 
   ProcessDied(false /* already_dead */, nullptr);
@@ skipping 1081 matching lines @@
   LOG(ERROR) << "Terminating render process for bad Mojo message: " << error;
 
   // The ReceivedBadMessage call below will trigger a DumpWithoutCrashing. Alias
   // enough information here so that we can determine what the bad message was.
   base::debug::Alias(&error);
   bad_message::ReceivedBadMessage(process.get(),
                                   bad_message::RPH_MOJO_PROCESS_ERROR);
 }
 
 }  // namespace content