Check that all RenderProcessHost(s) are terminated.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 99d9a89d9d0b3fd6cae4b2f8db519912c9d9e145..943b2be735f60677e9dcc3396db5e2c6aa158958 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -1084,6 +1084,11 @@ void BrowserMainLoop::ShutdownThreadsAndCleanUp() {
       }
       case BrowserThread::IO: {
         TRACE_EVENT0("shutdown", "BrowserMainLoop::Subsystem:IOThread");
+        // IO thread is about to be destoyed.
+        // All IO-thread resources held by RenderProcessHost(s) must have been
+        // released by now, which happens when IPC channel to the renderer
+        // process is destoyed.
+        CHECK(!RenderProcessHostImpl::HasAnyConnection());

[alokp, 2016/07/08 17:30:15]

jam@: Is this a valid assumption?

We are hitting a CHECK in AudioManager destructor which verifies that no audio
output stream outlives AudioManager. The streams owned by RenderProcessHostImpl
are released when IPC channel is reset. From the crash reports it seems that we
have instances of RPHI with valid IPC channel.

We explicitly cleanup other child process during shutdown:
https://cs.chromium.org/chromium/src/content/browser/browser_process_sub_thre...

But I did not find anything for renderer processes. Should I expect all
instances of RPHI be destroyed or at least disconnected by now?

         ResetThread_IO(std::move(io_thread_));
         break;
       }