Stop each ChromeThread before nulling out the entry in chrome_threads_. This...

chrome/browser/chrome_thread.cc

Index: chrome/browser/chrome_thread.cc
===================================================================
--- chrome/browser/chrome_thread.cc	(revision 30973)
+++ chrome/browser/chrome_thread.cc	(working copy)
@@ -41,6 +41,11 @@
 }
 
 ChromeThread::~ChromeThread() {
+  // Stop the thread here, instead of the parent's class destructor.  This is so
+  // that if there are pending tasks that run, code that checks that it's on the
+  // correct ChromeThread succeeds.
+  Stop();
+
   AutoLock lock(lock_);
   chrome_threads_[identifier_] = NULL;
 #ifndef NDEBUG