Delay destructing ChildDiscardableSharedMemoryManager

content/renderer/render_thread_impl.cc

 // Copyright (c) 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.
 
 #include "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 947 matching lines @@
 #if defined(OS_WIN)
   // Clean up plugin channels before this thread goes away.
   NPChannelBase::CleanupChannels();
 #endif
 
   ChildThreadImpl::Shutdown();
 
   // Shut down the message loop and the renderer scheduler before shutting down
   // Blink. This prevents a scenario where a pending task in the message loop
   // accesses Blink objects after Blink shuts down.
-  // This must be at the very end of the shutdown sequence. You must not touch
-  // the message loop after this.
   renderer_scheduler_->Shutdown();
-  main_message_loop_.reset();
+  if (main_message_loop_)
+    main_message_loop_->RunUntilIdle();
+
   if (blink_platform_impl_) {
     blink_platform_impl_->Shutdown();
+    // This must be at the very end of the shutdown sequence.
+    // blink::shutdown() must be called after all strong references from
+    // Chromium to Blink are cleared.
     blink::shutdown();
   }
 
+  // Delay shutting down DiscardableSharedMemoryManager until blink::shutdown
+  // is complete, because blink::shutdown destructs Blink Resources and they
+  // may try to unlock their underlying discardable memory.
+  ChildThreadImpl::ShutdownDiscardableSharedMemoryManager();
+
+  // The message loop must be cleared after shutting down
+  // the DiscardableSharedMemoryManager, which needs to send messages
+  // to the browser process.
+  main_message_loop_.reset();
+
   lazy_tls.Pointer()->Set(NULL);
 }
 
 bool RenderThreadImpl::Send(IPC::Message* msg) {
   // Certain synchronous messages cannot always be processed synchronously by
   // the browser, e.g., putting up UI and waiting for the user. This could cause
   // a complete hang of Chrome if a windowed plugin is trying to communicate
   // with the renderer thread since the browser's UI thread could be stuck
   // (within a Windows API call) trying to synchronously communicate with the
   // plugin.  The remedy is to pump messages on this thread while the browser
@@ skipping 1137 matching lines @@
 }
 
 void RenderThreadImpl::PendingRenderFrameConnect::OnConnectionError() {
   size_t erased =
       RenderThreadImpl::current()->pending_render_frame_connects_.erase(
           routing_id_);
   DCHECK_EQ(1u, erased);
 }
 
 }  // namespace content