Enable spare RenderProcessHost to be preinitialized.

content/public/test/mock_render_process_host.h

Index: content/public/test/mock_render_process_host.h
diff --git a/content/public/test/mock_render_process_host.h b/content/public/test/mock_render_process_host.h
index f2802c98ae8a82fe397718d1a01f4a5343bbd45e..1a318caade0b002df08e3971ffb3662fd395daf9 100644
--- a/content/public/test/mock_render_process_host.h
+++ b/content/public/test/mock_render_process_host.h
@@ -131,6 +131,8 @@ class MockRenderProcessHost : public RenderProcessHost {
   bool IsUnused() override;
   void SetIsUsed() override;
 
+  bool HostHasNotBeenUsed() override;
+
   // IPC::Sender via RenderProcessHost.
   bool Send(IPC::Message* msg) override;
 
@@ -200,6 +202,11 @@ class MockRenderProcessHostFactory : public RenderProcessHostFactory {
   // to remove it from |processes_| to prevent it from being deleted twice.
   void Remove(MockRenderProcessHost* host) const;
 
+  // Retrieve the current list of mock processes.
+  std::vector<std::unique_ptr<MockRenderProcessHost>>* GetProcesses() {
+    return &processes_;
+  }
+
  private:
   // A list of MockRenderProcessHosts created by this object. This list is used
   // for deleting all MockRenderProcessHosts that have not deleted by a test in