Fix NaCl plugin shutdown when running the Chrome PPAPI proxy.

webkit/plugins/ppapi/ppapi_plugin_instance.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 "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
@@ skipping 384 matching lines @@
 // then it needs to keep its own reference on the stack.
 
 void PluginInstance::Delete() {
   // Keep a reference on the stack. See NOTE above.
   scoped_refptr<PluginInstance> ref(this);
   // Force the MessageChannel to release its "passthrough object" which should
   // release our last reference to the "InstanceObject" and will probably
   // destroy it. We want to do this prior to calling DidDestroy in case the
   // destructor of the instance object tries to use the instance.
   message_channel_->SetPassthroughObject(NULL);
-  instance_interface_->DidDestroy(pp_instance());
+  // If this is a NaCl plugin instance, allow the trusted NaCl plugin to start
+  // its own shutdown before the untrusted plugin, which may hang.
   if (nacl_plugin_instance_interface_.get())
     nacl_plugin_instance_interface_->DidDestroy(pp_instance());

[dmichael (off chromium), 2012/08/08 22:28:52]

This *should* kill the sel_ldr process where the nacl app is running. Not sure
why it isn't working :-/

+  instance_interface_->DidDestroy(pp_instance());

[bbudge, 2012/08/08 20:31:57]

If this hangs, is there an issue about the code that follows not being run? Or
is hanging not possible?

[dmichael (off chromium), 2012/08/08 22:28:52]

Hmm, it *is* a synchronous message. But if the process is killed while handling
the message, we should get some kind of error?

I don't really understand why the order of these should matter. It seems like
there's a race condition, and somewhere we're not doing the right thing. Did you
ever find out if the audio was repeating on a short interval, or if the plugin
was clearly still producing audio?

 
   if (fullscreen_container_) {
     fullscreen_container_->Destroy();
     fullscreen_container_ = NULL;
   }
   container_ = NULL;
 }
 
 void PluginInstance::Paint(WebCanvas* canvas,
                            const gfx::Rect& plugin_rect,
@@ skipping 1830 matching lines @@
   screen_size_for_fullscreen_ = gfx::Size();
   WebElement element = container_->element();
   element.setAttribute(WebString::fromUTF8(kWidth), width_before_fullscreen_);
   element.setAttribute(WebString::fromUTF8(kHeight), height_before_fullscreen_);
   element.setAttribute(WebString::fromUTF8(kBorder), border_before_fullscreen_);
   element.setAttribute(WebString::fromUTF8(kStyle), style_before_fullscreen_);
 }
 
 }  // namespace ppapi
 }  // namespace webkit