Fix some unit_tests under PlzNavigate

content/public/test/test_renderer_host.h

Index: content/public/test/test_renderer_host.h
diff --git a/content/public/test/test_renderer_host.h b/content/public/test/test_renderer_host.h
index 3a645cf51c92f2da3aae875fd2ba889c050eb873..74bcb5769268d57f1ddfeebed91c2448a945ab3c 100644
--- a/content/public/test/test_renderer_host.h
+++ b/content/public/test/test_renderer_host.h
@@ -96,6 +96,23 @@ class RenderFrameHostTester {
   // Simulates a navigation stopping in the RenderFrameHost.
   virtual void SimulateNavigationStop() = 0;
 
+  // If we are doing a cross-site navigation, this simulates the current RFH

[clamy, 2016/08/30 23:08:38]

nit: s/RFH/RenderFrameHost here and below.

[scottmg, 2016/08/30 23:55:30]

Done.

+  // notifying that it has unloaded so the pending RFH is resumed and can
+  // navigate.
+  // PlzNavigate: the pending RFH is not created before the navigation commit,

[clamy, 2016/08/30 23:08:38]

This comment from "the pending RFH" to "deleted in the meantime" actually
belongs to where it was before. It describes why in this specific function we
need to call PrepareForCommit before trying to access the main or pending RFH.

For the comment, I would suggest getting the one from
TestRenderFrameHost::PrepareForCommit, and keeping most of the last paragraph.

[scottmg, 2016/08/30 23:55:30]

Done.

+  // so it is necessary to simulate the IO thread response here to commit in the
+  // proper renderer. It is necessary to call PrepareForCommit before getting
+  // the main and the pending frame because when we are trying to navigate to a
+  // webui from a new tab, a RenderFrameHost is created to display it that is
+  // committed immediately (since it is a new tab). Therefore the main frame is
+  // replaced without a pending frame being created, and we don't get the right
+  // values for the RFH to navigate: we try to use the old one that has been
+  // deleted in the meantime.
+  // Note that for some synchronous navigations (about:blank, javascript
+  // urls, etc.) there will be no NavigationRequest, and no simulation of the

[clamy, 2016/08/30 23:08:38]

Please remove the mention of NavigationRequest, since this is not a class we
expose outside of content/

[scottmg, 2016/08/30 23:55:30]

Done.

+  // network stack is required.
+  virtual void SimulateUnloading() = 0;
+
   // Calls OnDidCommitProvisionalLoad on the RenderFrameHost with the given
   // information with various sets of parameters. These are helper functions for
   // simulating the most common types of loads.