Change ChildProcess::set_main_thread registration to occur inside the RenderThreadImpl::Init method.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
===================================================================
--- content/renderer/render_thread_impl.cc	(revision 118690)
+++ content/renderer/render_thread_impl.cc	(working copy)
@@ -186,6 +186,9 @@
     initialize_com_.reset(new base::win::ScopedCOMInitializer());
 #endif
 
+  // Register this object as the main thread.
+  ChildProcess::current()->set_main_thread(this);

[jam, 2012/01/30 19:46:12]

nit: can we do this in ChildThread's constructor? we try to make all the
ChildProcess/ChildThread code take the same paths for simplicity

+
   // In single process the single process is all there is.
   suspend_webkit_shared_timer_ = true;
   notify_webkit_of_modal_loop_ = true;