Similar as extension, DOM UI needs to be created in its own process....

chrome/browser/tab_contents/render_view_host_manager_unittest.cc

Index: chrome/browser/tab_contents/render_view_host_manager_unittest.cc
===================================================================
--- chrome/browser/tab_contents/render_view_host_manager_unittest.cc	(revision 70598)
+++ chrome/browser/tab_contents/render_view_host_manager_unittest.cc	(working copy)
@@ -253,8 +253,6 @@
   EXPECT_TRUE(host);
   EXPECT_TRUE(host == manager.current_host());
   EXPECT_FALSE(manager.pending_render_view_host());
-  EXPECT_TRUE(manager.pending_dom_ui());
-  EXPECT_FALSE(manager.dom_ui());
 
   // It's important that the site instance get set on the DOM UI page as soon
   // as the navigation starts, rather than lazily after it commits, so we don't
@@ -263,9 +261,6 @@
   EXPECT_TRUE(host->site_instance()->has_site());
   EXPECT_EQ(url, host->site_instance()->site());
 
-  // Commit.
-  manager.DidNavigateMainFrame(host);

[Charlie Reis, 2011/01/07 23:40:37]

Let's keep this commit block as the last line of the test (below the DOMUI
related EXPECTs), just to prevent regressions in DidNavigateMainFrame in this
case.

-
   EXPECT_FALSE(manager.pending_dom_ui());

[Charlie Reis, 2011/01/07 23:40:37]

Let's put a comment above this line saying that the DOMUI is committed
immediately because the RenderViewHost has not been used yet.  It'll help others
understand why the change was needed.

   EXPECT_TRUE(manager.dom_ui());
 }