Ensure that in the SiteInstanceTest, no actual RenderProcessHosts are created.

content/browser/site_instance_impl_unittest.cc

Index: content/browser/site_instance_impl_unittest.cc
diff --git a/content/browser/site_instance_impl_unittest.cc b/content/browser/site_instance_impl_unittest.cc
index 5b7606d631081cf7c3fbb8ef2be11fcdb2bf19c1..55240913288a2ef8eb77f58d5ee2fd4e3460c6e7 100644
--- a/content/browser/site_instance_impl_unittest.cc
+++ b/content/browser/site_instance_impl_unittest.cc
@@ -94,6 +94,8 @@ class SiteInstanceTest : public testing::Test {
     old_browser_client_ = SetBrowserClientForTesting(&browser_client_);
     url_util::AddStandardScheme(kPrivilegedScheme);
     url_util::AddStandardScheme(chrome::kChromeUIScheme);
+
+    SiteInstanceImpl::set_render_process_host_factory(&rph_factory_);
   }
 
   virtual void TearDown() {
@@ -135,6 +137,7 @@ class SiteInstanceTest : public testing::Test {
 
   SiteInstanceTestBrowserClient browser_client_;
   ContentBrowserClient* old_browser_client_;
+  MockRenderProcessHostFactory rph_factory_;
 };
 
 // Subclass of BrowsingInstance that updates a counter when deleted and
@@ -551,8 +554,6 @@ static SiteInstanceImpl* CreateSiteInstance(BrowserContext* browser_context,
 // Test to ensure that pages that require certain privileges are grouped
 // in processes with similar pages.
 TEST_F(SiteInstanceTest, ProcessSharingByType) {
-  MockRenderProcessHostFactory rph_factory;
-  SiteInstanceImpl::set_render_process_host_factory(&rph_factory);
   ChildProcessSecurityPolicyImpl* policy =
       ChildProcessSecurityPolicyImpl::GetInstance();