Forcibly clear worker ref counts on shutdown.

content/public/test/mock_render_process_host.cc

Index: content/public/test/mock_render_process_host.cc
diff --git a/content/public/test/mock_render_process_host.cc b/content/public/test/mock_render_process_host.cc
index 38f45046e0f6b7a6d272d6b99e2541574e525cb7..6d20cc65a6f08ea4a5aaabc1da47ae90ebaabc86 100644
--- a/content/public/test/mock_render_process_host.cc
+++ b/content/public/test/mock_render_process_host.cc
@@ -302,6 +302,14 @@ void MockRenderProcessHost::DecrementSharedWorkerRefCount() {
   --worker_ref_count_;
 }
 
+void MockRenderProcessHost::ForceReleaseWorkerRefCounts() {
+  worker_ref_count_ = 0;
+}
+
+bool MockRenderProcessHost::IsWorkerRefCountDisabled() {
+  return false;
+}
+
 void MockRenderProcessHost::PurgeAndSuspend() {}
 
 void MockRenderProcessHost::FilterURL(bool empty_allowed, GURL* url) {